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PLANT-BREEDING 




(gartitn=Craft Scries 

The Horticulturist's Rule-Book 
Plant-Breeding 



PLANT-BREEDING 



BEING SIX LECTURES UPON THE 

AMELIORATION OF DOMESTIC 

PLANTS 



BY 

L. H. BAILEY 



FOURTH EDITION 

WITH A NEW CHAPTER ON CURRENT 
PLANT-BREEDING PRACTICE 



Neijj gorfc 
THE MACMILLAN COMPANY 

LONDON: MACMILLAN & CO. Ltd. 
1906 

All rights reserved 



~1 



LIBRARY of CONGRESS 
Two Copies Received 

APR 25 1906 

opyrizht Entry 

ci^ss gl' " 




Xc. No, 



COPY B. 



XXc. N 






Coptbight, 1895, 1906, 
By L. H. BAILEY. 



Set up and electrotyped. Published December, 1895. Reprinted 
April, 1896; August, October, 1897; March, 1902; March, 1904. 
Fourth Edition, with additions, April, 1906. 



Norfoooft $resss 

J. S. Cushing & Co. — Berwick & Smith Co. 
Norwood, Mass., U.S.A. 



PREFACE. 

There is no subject associated with the care 
of plants respecting which there is so much mis- 
apprehension and imperfect knowledge, as that 
of the origination of new forms. Most of the 
scattered writing touching it treats the subject 
as if all our knowledge of the matter were and 
must be derived wholly from experiment. It 
therefore recites examples of how this and that 
new form has come to be, and has made little 
attempt to discover the fundamental causes of 
the genesis of the novelties. Horticulturists 
commonly look upon each novelty as an isolated 
fact, whilst we ought to regard each one as but 
an expression of some law of the variation of 
plants. It is the common notion, too, to con- 
sider any type of plant to- be essentially a fixed 
entity, and to regard any marked departure from 

the type as a phenomenon rather more to be 

v 



Vi PREFACE. 

wondered at than to be explained. It is evident, 
however, that one cannot understand the pro- 
duction of new varieties until he has grasped 
some of the fundamental principles of the on- 
ward progression of the vegetable kingdom. 
Any attempt, therefore, to explain the origin of 
garden varieties, and the methods of producing 
them, must be at the same time a contribution 
to the literature of the philosophy of organic 
evolution. 

I do not know of any explicit and sustained 
attempt to account for the evolution of all gar- 
den forms, and I have therefore brought together 
in this volume the subject-matter of various 
lectures which I have been in the habit of 
giving before my students. The first and 
third lectures were newly elaborated the present 
summer for two addresses before the class in 
biology which came together at the University 
of Pennsylvania, under the auspices of the 
American Society for the Extension of Univer- 
sity Teaching. The second lecture was first 
presented before the Massachusetts State Board 
of Agriculture, in Boston, December 1, 1891. 
In April, 1892, it was republished, with a bibli- 



PREFACE. Vll 

ography of the subject, by the Rural Publishing 
Co., under the title, " Cross-Breeding and Hybrid- 
izing." This publication is now out of print. 
I have made no attempt to collect lists or cata- 
logues of varieties, but have endeavored to make 
very brief statements of some of the underlying 
principles of the amelioration of plants, with only 
sufficient examples to fix them in the mind. 

I hope that teachers of horticulture and botany 
may find the book useful in their classes. When 
it is necessary to abridge the instruction or to 
present it to untrained students, only Lectures 
III. and V. may be used, for these contain the 
matters of greatest demonstrative importance. 

L. H. Bailey. 

Cornell University, 
Ithaca, N.Y., September 1, 1895. 



PREFACE TO THIRD EDITION. 

In the eight years since this book was sent to 
the printer, there have been great changes in our 
attitude toward most of the fundamental questions 
that are discussed in its pages. In fact, these 
years may be said to have marked a transition 
between two habits of thought in respect to the 
means of the evolution of plants, — from the points 
of view held by Darwin and the older writers to 
those arising from definite experimental studies 
in species and varieties. We have not given up 
the old nor wholly accepted the new, but it is 
certain that our outlook is shifting. So far as 
practical plant-breeding is involved, the changing 
attitude is concerned chiefly with discussions of 
the nature of varieties and the nature of hybridi- 
zation. 

The chief practical result of the discussion of 

the nature of varieties is a re-defining of what a 

viii 



PREFACE TO THIRD EDITION. IX 

variety is, whereby we have come to recognize the 
fact, more clearly than heretofore, that not all 
differences in plants are of equal importance or 
significance. 

The practical result of the discussions of hy- 
bridization is the growing belief that the offspring 
of hybridization follow definite laws. This state- 
ment seems to be wholly at issue with the tenor of 
Lecture II. ; but the apparent contradictions are 
largely such as follow from two sets of definitions 
of the ideas of " variety" and "hybrid." It must 
also be remembered that even if hybridization fol- 
lows definite laws, the practical results are com- 
monly so modified and obscured by interfering 
circumstances that safe predictions usually cannot 
be made. I had once thought of rewriting Lec- 
ture II., but on going over it again I found that 
the chief change that I should desire now to make 
would be a rephrasing in order to conform it to 
the method of current discussions. Moreover, we 
are not yet ready to make very positive discus- 
sions from the newer studies. The time cannot 
be far distant when the subject of plant-breeding 
will be rewritten from a new point of view. In 
the meantime, I hope that the new matter in 



X PREFACE TO THIRD EDITION. 

Lecture IV. may set the reader straight on some 
of the newer problems. 

The first issue of this book was made late in 
1895. The second edition was made early in 1902. 
In the meantime it had been twice reprinted. By 
an inadvertence, the second edition was not so 
marked on the title-page. In that edition the 
changes in the text were few. The only very im- 
portant departure was the publication of a bibli- 
ography. This bibliography had appeared with 
my paper on " Cross-Breeding and Hybridizing," 
which was published in 1892 as one of the Rural 
Library Series. It was purposely confined to 
such literature as English-speaking horticulturists 
would be most likely to find. The edition was 
soon exhausted, and many requests for this bibli- 
ography decided me to extend and republish it. 
In the present edition I have added somewhat to 
this bibliography (to the close of 1902), and have 
made some changes in the text ; but the leading 
change is the substituting of new matter for the 
old Lecture IV. 

L. H. Bailey 

Cornell University, 
Ithaca, N.Y., September 1, 1903. 



CONTENTS. 



LECTURE L 

The Fact and Philosophy of Variation • . 

I. The Fact of Individuality .... 
The seed-individual. 
The bud-individual. 

II. The Causes of Individual Differences 

a. Fortuitous variation .... 
6. Sex as a factor in the variation of plants 
C. Physical environment and variation . 

1. Variation in food supply 

2. Variation in climate . 

3. Change of seed. Bud-variation 
d. Struggle for life a cause of variation . 

III. The Choice and Fixation of Variations 



PAGB 

1 



8 

9 
11 
12 
16 
24 
28 
29 

31 



LECTURE II. 

The Philosophy of the crossing of Plants, consid- 
ered in Reference to their Improvement under 
Cultivation . . 39 

I. The Struggle for Life ..... 39 

II. The Division of Labor 42 

III. The Limits of Crossing • • • 44 

xi 



Xll 



CONTENTS. 



IV. Function of the Cross .... 

a. The gradual amelioration of the type 

b. Change of seed and crossing 

c. The outright production of new varieties 

V. Characteristics of Crosses .... 

VI. Uncertainties of Pollination 

Conclusion 



PAGE 

50 
50 
59 
64 

68 
83 
86 



Kule 



LECTURE III. 

How Domestic Varieties Originate . . . . 87 

I. Indeterminate Varieties 87 

II. Plant-breeding . 91 

Rule 1. Antagonistic features ... 95 
2. Quickest results in the most variable 

groups 96 

Breed for one thing at a time . . 98 
Contradictory attributes . . .98 
Characters of the entire plant most 

important 99 

Plants differ in hereditary power . 104 
Less marked variations more impor- 
tant 105 

Crossing a means, not an end . . 107 

Choice of parents to a cross . . 109 
The ideal should be mental . .112 
Seek to produce variation in the 

desired direction . . . .114 
Watch for bud- varieties . . .118 
Progress lies in selection . . . 120 
The type is kept up to standard by 
continued selection . . . 122 
Rule 15. The best final results are to be ob- 
tained by high tillage and intelli- 
gent selection .... 127 



Rule 3. 


Rule 4. 


Rule 5. 


Rule 6. 


Rule 7. 


Rule 8. 


Rule 9. 


Rule 10. 


Rule 11. 


Rule 12. 


Rule 13. 


Rule 14. 



CONTENTS. 



Xlll 



III, Specific Examples . . , 

The dewberry and blackberry 
The apple ... 

Beans 

Cannas . • • 



PAGE 

129 

129 
131 
135 
140 



LECTURE IV. 

Recent Opinions; being a Resume of the Investigations 
of De Vries, Mendel, and Others, and a Statement 
of the Current Tendencies of American Plant- 
breeding Practice 143 

144 

145 

155 
169 
175 
179 

181 

189 
202 



I. Some Becent Ideas on the Evolution of Plants 

a. Variation : De Vries . 

b. Heredity : Mendel 

c. Application to Plant-breeding 

d. Interpretation of Hybridism 

e. Conclusion . . • 

Mendelism in Wheat 

II. On Hybridization : De Vries 
III. The Forward Movement in Plant-breeding 



LECTURE V. 

Current Plant-breeding Practice .... 227 

I. Luther Burbank 238 

II. A Practical Plant-breeder 246 

III. The Experiment Station Work .... 255 
Breeding hardy fruits for the prairie north- 
west . 260 

Cornell timothy-breeding .... 266 



XIV 



CONTENTS. 



IV. United States Department of Agriculture . . 276 

Citrus-breeding 278 

Pineapple-breeding 283 

Cotton-breeding 284 

Wheat-breeding 291 

Method of pedigree records in the plant- 
breeding work of the Department of Agri- 
culture 308 



LECTURE VI. 

Pollination; or How to Cross Plants . . . 331 

I. The Structure of the Flower .... 331 

II. Manipulating the Flowers .... 344 

GLOSSARY 359 

BIBLIOGRAPHY 365 

INDEX 479 



PLANT-BREEDING 



PLANT-BREEDING. 



LECTURE I. 

THE FACT AND PHILOSOPHY OF VARIATION. 

There is no one fact connected with horticult- 
ure which so greatly interests all persons as the 
existence of numerous varieties of plants which 
seem to satisfy every need of the gardener. 
Whence came all this multitude of forms ? What 
are the methods employed in securing them ? Are 
they simply isolated facts or phenomena of gar- 
dening, or have they some relation to the broader 
phases of the evolution of the forms of life? 
These are some of the questions which occur to 
every reflective mind when it contemplates an 
attractive garden, but they are questions which 
seem never to be answered. Whatever attempt 
the gardener may make at answering them is 
either befogged by an effort to define what a vari- 
ety is, or else it consists in simply reciting how a 
few given varieties came to be known. But there 

B l 



2 FACT AND PHILOSOPHY OF VARIATION. 

must be some fundamental method of arriving at 
a conception of how the varieties of fruits and 
flowers and other cultivated plants have origi- 
nated. If there is no such method, then the 
origination of these varieties must follow no law, 
and the discussion of the whole subject is fruit- 
less. But we have every confidence in the con- 
secutive uniformity of the operations of nature, 
and it were strange if some underlying principle 
of the unfolding or progression of plant life does 
not dominate the origin of the varied and in- 
numerable varieties which, from time unknown, 
have responded to the touch of the cultivator. 
Let us first, therefore, make a broad survey of the 
subject in a philosophical spirit, and, later, discuss 
the more specific instances of the origination of 
varieties. 

I. The Fact of Individuality. 

There is universal difference in nature. No 
two living things are exact counterparts, for no 
two are born into exactly the same conditions and 
experiences. Every living object has individ- 
uality ; that is, there is something about it which 
enables the acute observer to distinguish it from 
all other objects, even of the same class or spe- 
cies. Every plant in a row of lettuce is different 
from every other plant, and the gardener, when 



INDIVIDUALITY. 3 

transplanting them, selects out, almost uncon- 
sciously, some plants which please him and others 
which do not. Every apple tree in an orchard of 
a thousand Baldwins is unlike every other one, 
perhaps in size or shape, or possibly in the vigor 
of growth or the kind of fruit it bears. Persons 
who buy apples for export knoAV that fruit from 
certain regions stands the shipments better than 
the same variety from other regions ; and if one 
were to go into the orchards where these apples 
are grown, he would find the owner still further 
refining the problem by talking about the merits 
of individual trees in his orchard. If one were 
to make the effort, he would find that it is pos- 
sible to distinguish differences between every two 
spears of grass in a meadow, or every two heads 
of wheat in a grain-field. 

All this is equivalent to saying that plants are 
infinitely variable. The ultimate causes of all 
this variation are beyond the purpose of the 
present discussion, but it must be evident, to 
the reflective mind, that these differences are 
the means of adapting the innumerable indi- 
viduals to every little difference or advantage 
in the environment in which they live. And if 
the result of variation is better adaptation to 
the physical conditions of life, then the same 
forces must have been present in the circum- 
stances which determined the birth of the indi- 



4 FACT AND PHILOSOPHY OF VARIATION. 

vidual. The variation in environment, therefore, 
must be the cause of much of the variation in 
plants, since differences in plants were positively 
injurious if it were possible for the conditions of 
environment to be the same. 

If no two plants are anywhere alike, then it is 
not strange if now and then some departure, more 
marked than common, is named and becomes a 
garden variety. We have been taught to feel 
that plants are essentially stable and inelastic, 
and that any departure from the type is an excep- 
tion and calls for immediate explanation. The 
fact is, however, that plants are essentially un- 
stable and plastic, and that variation between the 
individuals must everywhere be expected. This 
erroneous notion of the stability of organisms 
comes of our habit of studying what we call 
species. We set for ourselves a type of plant or 
animal, and group about it all those individuals 
which are more like this type than they are like 
any other, and this group we name a species. 
Nowadays, the species is regarded as nothing 
more than a convenient and arbitrary expression 
for classifying our knowledge of the forms of 
life, but the older naturalists conceived that the 
species is the real entity or unit in nature, and we 
have not yet wholly outgrown the habit of mind 
which was born of that fallacy. Nature knows 
nothing about species ; she is concerned with the 



INDIVIDUALITY. 5 

individual, the ultimate unit. This individual she 
moulds and fits into the chinks of environment, 
and each individual tends to become the more 
unlike its birthmates the more the environments 
of the various individuals are unlike. I would 
impress upon you, therefore, as a fundamental 
conception to the discussion of the general subject 
before us, the importance of the individual plant, 
rather than the importance of the species ; for 
thereby we put ourselves as nearly as possible in 
a sympathetic attitude with nature, and, resting 
upon the ultimate object of her concern, we are 
able to understand what may be conceived to be 
her motive in working out the problem of life. 
That I may still more forcibly emphasize this 
thought, let me recall to your minds the fact 
that the whole tendency of contemporary civili- 
zation, in sociology and religion, is to deal with 
the individual person and not with the mass. 
This is only an unconscious feeling after natu- 
ral methods of solving the most complex of 
problems, for it is exactly the means to which 
every organic thing has been subjected from the 
beginning. 

In looking for the ultimate unit or individuality 
or personality in nature, we must make a broad dis- 
tinction between the animal and the plant. Every 
higher animal is itself a unit ; it is one. It has 
a more or less definite span of life, and every part 



6 FACT AND PHILOSOPHY OF VARIATION. 

and organ contribute a certain indispensable part 
to the life and personality of the organism. No 
part is capable of propagating itself independently 
of the sex-organs of the animal, nor is it capable 
of developing sex-organs of its own. If any part 
is removed, the animal is maimed and perhaps it 
dies. The plant, on the contrary, has no definite 
or distinct autonomy. Most plants live an indefi- 
nite existence, dependent very closely upon the 
immediate conditions in which they grow. Every 
part or branch of the plant lives largely for itself, 
it is capable of propagating and multiplying itself 
when removed from the parent plant or the colony 
of branches of which it is a member, and it de- 
velops sex-organs and other individual features 
of its own. If any branch is removed, the tree 
or plant does not necessarily suffer; in fact, the 
remaining branches usually profit by the removal, 
a fact which shows that there is a competition, 
or struggle for existence, between the different 
branches or elements of the plant. The whole 
theory and practice of pruning rest upon the fact 
of the individual unlikenesses of the branches of 
plants ; and these unlikenesses are of the same 
kind and often of the same degree as those which 
exist between different plants which are grown 
from seeds. That is, the branches of a Crawford 
peach tree, for example, differ amongst themselves 
in size, shape, vigor, productiveness, and season of 



BUD-INDIVIDUALS. 7 

maturity, the same as any two or more separate 
Crawford trees, or any number of trees of other 
varieties, differ the one from the others. If any 
one of these branches or buds is removed and is 
grown into an independent tree, a person could 
not tell — if he were ignorant of its history — if 
this tree were derived from a branch or a seed. 
This proves that there is no essential unlikeness 
between branches and independent plants, except 
the mere accident that one grows upon another 
branch or plant whilst the other grows in the 
ground. But the branch may be severed and 
grown in the ground, and the seedling may be 
pulled up and grafted on the tree, and no one 
can distinguish the different origins of the two. 
And then, as a matter of fact, a very large pro- 
portion of our cultivated plants are not distinct 
plants at all, in the sense of being different crea- 
tions from seeds, but are simply the results of 
the division of branches of one original plant or 
branch. All the fruit trees of any one variety 
are obtained from the dividing up and multiplica- 
tion of the branches of the first or original tree. 

You are now curious to know how this orig- 
inal tree came to be, and this I hope to tell 
you before I am done ; but for the present, let 
me impress it upon you that it is equally possi- 
ble for it to have come from a seed, or to have 
sprung from a branch which some person had 



8 FACT AND PHILOSOPHY OF VARIATION. 

noticed to be very different from the associated 
branches in the tree- top. In other words, the 
ultimate unit or individual of variation is the 
bud and the bit of wood or tissue to which it is 
attached ; for every bud, like every seed, pro • 
duces an offspring which can be distinguished 
from every other offspring whatsoever. 

II. The Causes of Individual Differences. 

We have now gotten back to the starting-point, 
to that unit with which nature begins to make 
her initial differences or individualities ; that is, 
to the point where variations arise. This unit 
is the bud and the seed, — one sexless, or the 
offspring of one parent ; the other sexual, or the 
offspring of two parents. Now, inasmuch as 
the horticultural variety is only a well-marked 
variation which the gardener has chanced to 
notice and to propagate, it follows that the only 
logical method of determining how garden vari- 
eties originate is to discover the means by which 
plants vary or differ one from another. 

There is probably no one fact of organic nature 
concerning the origin of which modern philoso- 
phers are so much divided as the genesis or 
reasons for the beginnings of variations or dif- 
ferences. It seems to be an inscrutable problem, 
and it would be useless, therefore, for us to at- 



FORTUITOUS VARIATION. 9 

tempt to discover these ultimate forces in the 
present hour. Still, we must give them sufficient 
thought to enable us to satisfy our minds as to 
how far these variations may be produced by 
man ; and, in doing this, we must discover at 
least the underlying philosophy of plant variation. 
It is the nature of organisms to be unlike their 
parents and their birthmates. Why? 

a. Fortuitous Variation. 

It will probably never be possible to refer every 
variation to a distinct cause, for it is probable that 
some of them have no antecedent. If we con- 
ceive of the forms of life as having been created 
with characters exactly uniform from generation 
to generation, then we should be led to look for 
a distinct occasion or cause for every departure 
from the type ; but we know, as I have already 
pointed out, that heredity by its very nature is 
not so exact as to carry over every attribute, and 
no other, of the parent to the offspring. Elas- 
ticity, plasticity, is a part of the essential consti- 
tution of all organic beings. There is probably 
no inherent tendency in organisms towards any 
ultimate or predetermined completion of form, as 
the older naturalists supposed, but simply a laxity 
or indefiniteness of constitution which is expressed 
in numberless minor differences in individuals. 



10 FACT AND PHILOSOPHY OF VARIATION. 



That is, some variation is simply fortuitous, an 
inevitable result of the inherent plasticity of 
organisms, and it has no immediate inciting 
cause. If we were to assume that every minor 
difference is the result of some immediate cause, 
then we should expect every individual plant or 
animal to fill some niche, to satisfy some need, to 
produce the definite effect for which the cause 
stands. But it is apparent to one who contem- 
plates the operations of nature that very many — 
certainly more than half — of the organisms which 
are born are not useful to the perpetuity of the 
species and very soon perish. From these fortui- 
tous variations nature selects, to be sure, many 
individuals to be the parents of other generations 
because they chance to be fitted to live, but this 
does not affect the methods or reasons of their 
origin. It is possible that, whilst many of these 
mere individual differences have no direct and 
immediate cause, they may still be the result of a 
devious line of antecedent causes long since so 
much diffused and modified that they will remain 
forever unrecognizable ; but even if so, the fact 
still remains that these present differences or 
variations may be purposeless, and it is quite as 
well to say that they exist because it is a part 
of the organic constitution of living things that 
unlike produces unlike. 



SEX AND VARIATION. 11 

b. Sex as a Factor in the Variation of Plants. 

All plants have the faculty, either potential or 
expressed, of propagating themselves by means 
of buds, or asexual parts. This is obviously the 
cheapest and most direct possible method of propa- 
gation for many-membered plants, since it requires 
no special reproductive organization and energy, 
and, as only one parent is concerned in it, there 
is none of the risk of failure which resides in any 
mode of propagation in which two parents must 
find each other and form a union. There must 
be some reason, therefore, for the existence of 
such a costly mechanism as sex aside from its use 
as a mere means of propagation. It may be said 
that it exists because it is a means of more rapid 
multiplication than bud-propagation, but such is 
not necessarily the fact. There are many plants 
which produce buds as freely as they produce 
seeds ; and then, if mere multiplication were the 
only destiny of the plant, bud-production would 
no doubt have greatly increased to have met the 
demand for new generations. The chief reason 
for the existence of sex in the vegetable world 
seems to be the need for a constant rejuvenation 
and modification of the offspring by uniting the 
features of two individuals into one. There thus 
arises from every sexual union a number of new 
or different forms from which nature may select 



12 FACT AND PHILOSOPHY OF VARIATION. 

the best, — that is, those best fitted to live in the 
conditions in which they chance to be placed. 
But whilst sex is undoubtedly one of the most 
potent sources of present unlikenesses, it is not 
necessarily an original cause of individual differ- 
ences, since the two parties to any sexual con- 
tract must be unlike before they can produce 
unlike. When once the initial unlikenesses were 
established, every new sexual union would pro- 
duce new combinations, so that now, when every 
new form, from whatever source it appears, comes 
into existence, there are other intimately related 
forms with which it may cross. This state of 
things has existed to a greater or less degree from 
the moment sex first appeared, so that the organic 
world is now endlessly varied as the result of a 
most complex ancestry. 

The variety which sexual union has introduced 
into the world performs such an important part in 
the evolution of the forms of plants, and the prob- 
lems which it presents are so complex, that I shall 
leave the Avhole subject for an independent dis- 
cussion (Lecture II.). 

c. Physical Environment and Variation. 

Every phase and condition of physical circum- 
stances, which are not absolutely prohibitive of 
plant life, have plants which thrive in them. 



ENVIRONMENT AND VARIATION. 13 

Every soil and climate, every degree of humidity, 
hills, swamps, and ponds, — every place is filled 
with plants. Even the trunks and branches of 
trees support other plants, as epiphytes and para- 
sites. That is, plants have adapted themselves to 
every physical environment ; or, to turn the propo- 
sition around, every physical environment pro- 
duces adaptive changes in plants. There are 
those, like Weismann and his adherents, who 
contend, from purely speculative reasons, that 
these changes do not become hereditary or perma- 
nent until they have influenced a certain physio- 
logical substance which is assumed to reside in 
the reproductive regions of the organism, and 
that all those changes which have not yet reached 
this germ-plasm are, therefore, lost, or die with 
the organism. It is not necessary to combat this 
philosophy, for we know, as a matter of common 
horticultural experience, that every change or va- 
riation in any organism — unless it proceeds from 
mere accident or mutilation — may become heredi- 
tary or be the beginning of a new variety ; it is 
only necessary, therefore, for the Weismannians to 
assume — as they are always ready to do — that 
any variation which has become fixed or permanent 
has already affected the germ. Their assumption 
needs only another assumption to prove it, and, 
therefore, when we are considering merely plain 
matters of fact and experience, we need give little 



14 FACT AND PHILOSOPHY OF VARIATION. 

attention to the subtleties of this Neo-Darwinian 
philosophy. 

Weismann teaches that "acquired characters," 
or those variations which first appear in the life- 
time of the individual because of the influences of 
environment, are lost, because they have not yet 
affected the reproductive substance. But if these 
characters are induced by the effect of impinging 
environment during two or more generations, they 
may come to be so persistent that the plant can- 
not throw them off, and they become, thereby, a 
part of the hereditary and non-negotiable prop- 
erty of the species. Now, it is apparent that in 
one or another of the generations which are thus 
acted upon by the environment, there must be a 
beginning towards the fixing or hereditable per- 
manency of the new form, and we might as well 
assume that this beginning takes place in the first 
generation as in the last, since there can be no 
proof that it does not take place in either one. 
The tendency towards fixity, if it exists at all, 
undoubtedly originates at the very time that the 
variation itself originates, and it is only sophistry 
to assume that the form appears at one time and 
the tendency towards permanence at another time. 
Since plants fit themselves into their circumstances 
by means of adaptive variations, we must con- 
clude that all adaptive variations have the power 
of persisting, upon occasion. 



NATAL AND POST-NATAL VARIATION. 15 

All these remarks, whilst somewhat abstruse, 
have a most important bearing upon the phi- 
losophy of the origin of garden varieties, because 
they show, first, that changes in the conditions in 
which plants grow introduce modifications in the 
plants themselves, and second, that wherever any 
modification occurs it is probable that it may be 
fixed and perpetuated. 

It is necessary, at this point, that we distin- 
guish between natal and post-natal variations ; 
that is, between those variations which are born 
with plants, and those which appear, as a result of 
environment, after the plant has begun to grow. 
It is commonly assumed that the form and general 
characters of the plant are already determined in 
the seed, but a moment's reflection will show that 
this is far from the truth. One may sow a hun- 
dred selected peas, for instance, all of which may 
be alike in every discernible character. If these 
are planted in a space a foot square, it will be 
found, after two or three weeks, that some indi- 
viduals are outstripping the others, although all 
of them came up equally well and were at first 
practically indistinguishable. This means that, 
because of a little advantage in food or moisture, 
or other circumstance, some plants have obtained 
the mastery and are crowding out the less fortu- 
nate ones. Here is a variation taking place before 
our very eyes, and we may be able to see the exact 



16 FACT AND PHILOSOPHY OF VARIATION. 

cause of it. Moreover, variations which originate 
in this way may pass down to the offspring 
through the seeds, as in the case of " viney " peas, 
which are grown on too rich soil. All this is a 
matter of the commonest observation with the 
gardener, who is so accustomed to seeing great 
differences arise in batches of plants, all of which 
start equal and with an equal chance, that he 
never thinks to comment upon the occurrence. 
In fact, the theory and practice of agriculture 
rest upon the fact that plants can be modified 
greatly by the conditions in which they grow, 
after they have become thoroughly established in 
the soil. Plants may start equal, but may differ 
widely at the harvest ; and this difference may be 
controlled to a nicety by the cultivator. Every 
farmer knows, too, that the best results for the 
succeeding year are to be got only when he selects 
seeds from the best which he has been able to pro- 
duce this year. So, given uniformity or equality 
at the start, the operator moulds the individual 
plants largely at his will. 

Having noticed that physical environments ma v 
modify plants, we are now ready to consider just 
what changes in these circumstances of plant life 
are most fruitful in the production of new forms. 

1. Variation in Food Supply. — The greater 
part of the changes in the physical conditions 
of life hinge upon the relative supply of food. 



FOOD SUPPLY AND VARIATION. 17 

Climbing plants assume their form because, by 
virtue of the divergence of character, they are 
enabled to lit themselves into places which other 
plants cannot occupy. They rear their foliage 
into the air, where food and sunlight are unappro- 
priated. The lower branches of the tree-top die, 
and the others thereby appropriate the more food 
and grow the faster. The entire practice of agri- 
culture is built upon the augmentation of the 
food supply. For this purpose, we set the plants 
in isolated positions, we till the ground, keep 
down other plants or weeds, add plant food to 
the soil, and prune the tree and thin the fruit. 

Thomas Andrew Knight, the chief of horticul- 
tural philosophers, appears to have been the first 
to clearly enunciate the law that excess of food 
supply is the most prolific cause of the variation 
of plants. Darwin subscribes to it without re- 
serve : " Of all the causes which induce varia- 
bility, excess of food, whether or not changed in 
nature, is probably the most powerful." Alex- 
ander Braun, an earlier philosophical writer on 
natural history, said that "it appears rather, on 
the whole, as if the unusual conditions favor- 
able to a luxuriant state of development, afforded 
by cultivation, awakened in the plant the inward 
impulse to the display of all those variations pos- 
sible within the more or less narrowly circum- 
scribed limits of the species." It is generally 



18 FACT AND PHILOSOPHY OF VARIATION. 

agreed by those who have given the matter much 
thought, that an excess of food above the amount 
normally or habitually received is one of the very 
chief, if not the most dominant, causes of indi- 
vidual differences in plants. Certainly every 
farmer and gardener knows that the richer the 
soil in available plant food, the stronger and the 
more abnormal and unusual his product will be. 

If, then, excess of food supply is a strong factor 
in the modification of plants, and if the one fun- 
damental aim of agriculture is to supply food in 
excess of natural conditions, it must naturally 
follow that cultivated plants should be of all 
others the most variable. This is notably true. 
Now, the first variation which usually comes of 
this liberal food supply is increase in mere big- 
ness. Probably every plant which has ever been 
cultivated has increased its stature or the size of 
some or all of its parts. Moreover, this is gener- 
ally the direct object of cultivation, — to secure 
larger herbage, fruits, seeds, or flowers. Inci- 
dentally, we find here an indubitable proof of the 
truth of the hypothesis of evolution, for if it were 
impossible for plants to vary or to assume new 
characters, there would be no cultivation and no 
agriculture; for there would be little object in 
cultivating a product if it grew equally well in 
the wild. 

This variation into mere bigness is more impor- 



BREAKING THE TYPE. 19 

tant than it may seem at first sight. All thought- 
ful horticulturists agree in believing that the first 
thing to be done in ameliorating any plant is to 
"break the type," that is, to cause it to vary. 
The particular direction of variation is not so 
important, at first; for all experience has shown 
that if once the seedlings of a plant begin to 
depart from the parental type, other and various 
modifications will soon follow. If a plant is once 
strongly modified in size, variations in shape, 
color, flavor, or other attributes are forthcoming. 
This apparent accumulation of variation seems at 
first to be incapable of scientific explanation, but 
the reasons for it are not difficult to understand 
when once they are presented. 

When plants are placed in new conditions, 
whether in the wild or in cultivation, then they 
begin to vary, but usually only in one direction 
at first, although the amount of the variation, and 
sometimes the kind, is determined very largely 
by the nature and the extent of the change in the 
conditions. This initial variation, particularly 
when plants are transferred to cultivated areas, 
is generally in the direction of greater size con- 
sequent upon the greater amount of food. This 
initial variation is generally soon followed by 
others in various directions, and from these the 
cultivator may be able to establish new varieties. 
We now ask ourselves why these many variations 



20 FACT AND PHILOSOPHY OF VARIATION. 

appear when once the type begins to modify itself. 
Consider the fact that the world is now full of 
plants. In untamed nature, not one more plant 
can grow unless another plant dies. All plants, 
therefore, are held down to narrow limits of num- 
bers, and since there are so few individuals, — 
in comparison with the seeds and buds which 
each plant produces for the chance of multiplying 
itself, — there must be, also, few kinds and degrees 
of individual differences. The farther and more 
freely a plant distributes itself, the greater must 
be the differences between the various individuals, 
because they must adapt themselves to a wider 
range of conditions. All plants are held in equi- 
librium, so to speak; but the plant organism is 
plastic by nature and quickly responds to every 
touch of environment; so, as soon as the pressure 
is removed in any direction, the plant at once 
springs into the breach. Recall the monotonous 
vegetation of the deep forest, where the battle 
of centuries has subdued all but the strongest. 
Clear away the forest, and then observe the 
fierce scramble for place and life amongst a multi- 
tude of forms which, spring in for an opportunity 
to better their conditions. In a few years more, 
the tender low herbs have gone. The briars and 
underbrush have usurped the land. As time goes 
on, one species after another perishes, and when 
the place is again reforested, two or three species 



EQUILIBRIUM IN NATURE. 21 

hold undisputed sway over the land. The pop- 
lars which followed the pines have long since per- 
ished and pines again dominate the forest. Or, 
if the area were turned to pasture a few years 
after the woods were removed, the herbs and 
bushes die with the browsing, and in time the 
June grass covers the whole landscape with the 
mantle of conquest. So plants may be said to 
be always ready to fill new places in the polity 
of nature by adapting themselves to the new cir- 
cumstances as they grow into them. The appear- 
ing of any one marked variation, therefore, is 
evidence that the plant has found a new condi- 
tion, that the pressure is somewhat lifted, and 
that its whole plastic organization will soon re- 
spond to the new environment. It is apparent, 
then, how the simplest and rudest cultivation has 
been able, through the centuries, to so profoundly 
modify our domestic plants that we are often 
unable to recognize the forms from which they 
sprung. 

We must not forget to notice, at this point, 
that the food supply differs amongst the various 
branches of the same plant. Some branches, by 
reason of position with reference to the main 
trunk or with reference to air and sunlight, or, 
because of a better start in the beginning as a 
result of some incidental advantage, gain the 
mastery over others and crowd them out. We 



22 FACT AND PHILOSOPHY OF VARIATION. 

have already seen that no two branches on a plant 
are alike ; and we are now able to understand that 
sports or bud-varieties are no more inexplicable 
than seed- varieties are. 

Cultivation is really but an extension or intensi- 
fication of nature's methods of dealing with the 
plant world. The ultimate object of both nature 
and man is to supply more food. The variations 
which arise from the effects of mere cultivation, 
therefore, are in kind very like those which nature 
produces, the chief difference being that of degree. 
The accustomed operations of the farmer, there- 
fore, have been powerful agents in the evolution 
of vegetable forms. The ways in which cultiva- 
tion affords a more liberal food supply are as fol- 
lows : — 

1. By isolating the individual plant. The 
husbandman sets each plant by itself, and then 
protects it by destroying the weeds or plants 
which endeavor to crowd it out. There is a 
partial exception to this in the "sowed crops," 
like the grains, and it is noticeable that variation 
in these plants is usually less marked than in the 
"hoed crops." 

2. By giving the plant the advantage of posi- 
tion, whereby it is allowed the most congenial 
exposure to sun and contour of land. 

3. By increasing the fertility of the soil, either 
by tillage or the direct application of plant 



MEANS OF AUGMENTING FOOD SUPPLY. 23 

food, or both. Rich and moist soils tend to 
" break " the type, — or to cause initial varia- 
tions, — to produce verdant colors and loss of 
saccharine and pungent qualities, to induce re- 
dundant growth, and to delay maturity and 
thereby to render plants tender to cold winter 
climates. 

4. By thinning the tops of plants and the 
fruits, whereby the remaining parts receive an 
amount of food in excess of the habitual allow- 
ance. 

5. By divergence of character in associated 
plants. It is well known that a field which is 
planted so thickly to corn that it cannot grow 
more with profit, may still grow pumpkins be- 
tween. The pumpkins and the corn are so unlike 
in form that they complement each other, the one 
filling the niche which the other is not fitted to 
occupy. We have already seen that a copse ever 
so full of bushes may still grow vines. A meadow 
which is full of timothy may still grow clover 
in the bottom, and land which is covered with 
apple trees still grows weeds beneath. " The 
more diversified the descendants from any one 
species become in structure, constitution, and 
habits," writes Darwin, "by so much will they 
be better enabled to seize on many and widely 
diversified places in the polity of nature, and so 
be enabled to increase in numbers," 



24 FACT AND PHILOSOPHY OF VARIATION. 

2. Variation in Climate. — The fact that any 
distinct climatic region usually has plants which 
are very closely related to those of other climatic 
regions in the same zone, points strongly to the 
probable profound modification of plants by cli- 
mate. And, furthermore, we should expect that if 
the food environment modifies plants, the climatic 
environment must have the same power. More- 
over, there is abundant historical and experimental 
proof that climate is capable of greatly modifying 
the vegetable kingdom. There are those who 
contradict any great effect of climate in the varia- 
tion of plants, and acclimatization has been even 
stoutly denied. These persons make the mistake 
of asking that a visible modification take place at 
once upon the transfer of a plant from one climate 
to another, and they also err in supposing that a 
plant can adapt itself to a cold climate only by 
developing a capability to withstand more cold. 
Indian corn is sometimes cited as proof that 
plants do not become acclimatized, for it is as 
tender to frost now as ever, for all that Ave know. 
Yet this very plant affords a most unequivocal 
example of complete acclimatization, because it 
has shortened its period of growth fully one-half 
to enable it to escape the cold of the north. 

The influence of a change of climate upon 
plants, or, what may amount to the same thing, 
the result of a transfer of plants to new climates, 



CLIMATE AND VARIATION. 25 

is so complex and so general that no detailed dis- 
cussion of the subject can be made at this time. 
It will answer our present purpose to briefly 
designate the ways in which climate modifies 
plants : — 

1. Climate greatly modifies the stature of plants. 
They become dwarfer in high latitudes and alti- 
tudes. 

2. It modifies form. Plants tend to be broader- 
headed, and also more prostrate, in high latitudes 
and altitudes. 

3. Proportionate leanness generally increases, 
at the same time. 

4. There is, also, often a gain in comparative 
fruitfulness following transfer towards the poles. 

5. The colors of leaves, flowers, fruits, and 
seeds are greatly influenced by climate, there 
being a general tendency, in plants of temperate 
regions, to augmentation in intensity of colors as 
they are carried towards the poles. 

6. There is modification in the flavor and es- 
sential ingredients of various parts, following a 
change of climate. 

7. There is a variation in variability itself. The 
more difficult the climate in which a plant finds 
itself, the more it tends to vary to meet the uncon- 
genial environments. In the high north, many 
plants are so variable that the marks used to iden- 
tify the species in other latitudes are often lost. 



26 FACT AND PHILOSOPHY OF VARIATION. 



8. There may be a profound variation or modi- 
fication in constitution and habit by which plants 
become acclimatized, or enabled to endure a cli- 
mate at first injurious to them. This may occur 
by a variation in the constitution of the descend- 
ants, which enables them to endure directly more 
untoward conditions. It generally comes about, 
however, through a change in habit, by which 
plants, when transferred towards the poles, shorten 
their season of growth or even become annuals. 
Plants become more sensitive to spring tempera- 
tures in cold climates, so that they start relatively 
much earlier in the season — that is, at a lower 
sum-temperature — than they do in warm climates. 
Any one who has passed the springtime in both 
the North and South must have noticed how much 
more suddenly the vegetation comes forward in 
the North; and it is surprising how the spring- 
sowed crops accelerate their growth in the North 
over those in the South. 

The characters which result from a change of 
climatic environment are peculiarly within the 
control of the agriculturist, for a leading factor 
in his business is the transfer of plants far and 
wide over the earth. So it has come that the 
staple varieties of the important grains and fruits 
are unlike in Europe and America and in all great 
geographical areas, although all the various forms 
may have sprung from one ancestor within historic 






CLIMATE AND VARIATION. 27 

times. A new country is stocked with varieties 
from the mother country ; but in the course of 
a few generations it is found that the varieties 
in cultivation are unlike the ones originally in- 
troduced, and from which they came. As wild 
plants have become separated from each other as 
species in the different geographical regions, so 
the cultivated plants soon begin to folloAv similar 
lines of divergence. In the beginning of the colo- 
nization of this country, for example, all the vari- 
eties of apples were of European origin. But in 
1817, over sixty per cent of the apples recommended 
for cultivation here were of American origin, that 
is, American-grown seedlings from the original 
stock. At the present time, fully ninety per cent 
of the popular apples of the Atlantic states are 
American productions. The northern states of 
the Mississippi valley, to which most of our east- 
ern apples are not adapted, are now witness- 
ing a similar transformation in the adaptation 
and modification of the varieties introduced 
from the East and from Russia. The newly 
introduced Japanese plums are conceded to be 
great acquisitions to our fruit-growing, but no 
doubt the best results are yet to come with the 
origination of domestic varieties of them. So 
there is an irresistible tendenc}^ towards a di- 
vergence of forms in different continental or 
geographical regions, and much of the inevi- 



28 FACT AND PHILOSOPHY OF VARIATION. 

table result is no doubt chargeable to climatic 
environment. 

3. Change of seed. Bud-variation. — I will 
pause for a moment to consider two agencies or 
phenomena which are often associated with the 
genesis of varieties. One of these is the fact 
that the simple change of seed from one locality 
to another generally gives a larger or better 
product or even more marked variation. Mere 
transfer of seed is not of itself, however, a cause 
of variation. The change is beneficial because 
it fits together characters and environments which | 
are not in equilibrium with each other. A plant 
which is grown for several years in one set of con- 
ditions becomes fitted into them, so to speak, and 
is in a comparative state of rest. When the plant 
or its progeny is taken to other conditions, all the 
adjustments are broken up, and in the refitting to 
the new circumstances new or strange characters 
are apt to appear. We shall leave this subject 
for the present, expecting to give it a fuller 
treatment in the second lecture. 

Bud-variation, or sport, is a name given to 
those branches which are so much unlike the 
normal plant in any particular that they attract 
attention. Many garden varieties are simply 
multiplications of such abnormal branches. This 
bud-variation is commonly held to be such an 
unusual and inexplicable phenomenon that it is 



STRUGGLE FOR LIFE AND VARIATION. 29 

considered apart from all the general discussions 
of variation. It is not, of course, a cause of vari- 
ability, but simply an effect of some antecedent, 
the same as seed-variation is. We have already 
seen that all the different branches, or even joints, 
of any plant are, in a very important sense, dis- 
tinct individuals, since every one develops its 
own organs, each is capable of reproducing itself 
independently, and each is unlike every other 
because it is acted upon differently by environ- 
ment and food supply. It is not strange, there- 
fore, that some of these individuals should now 
and then depart very widely from the ordinary 
type, and thereby attract the attention of a gar- 
dener, who would forthwith make cuttings or set 
grafts from the part. Every branch is a bud- 
variety, just as truly as every seedling is a seed- 
variety, — since no seedling is ever exactly like its 
parent, — and there should be no greater mystery 
connected with the sports of buds than there is 
with the variations from seeds, for the causes 
which produce the one may be and are equally ^y 
competent to produce the other. 

d. Struggle for Life a Cause of Variation. 

We have seen that the world is full of plants. 
There is room for more only as the present indi- 
viduals die. Yet nearly every species produces 



30 FACT AND PHILOSOPHY OF VARIATION. 

a great number of seeds, and makes a most stren- 
uous effort to multiply its kind. Any one plant, 
if left to itself, is capable of covering the earth in 
a comparatively short time. A fierce struggle for 
a chance to live is therefore inevitable. This con- 
flict is most apparent to the general observer in 
the springtime, when every "herb yielding seed 
after his kind, and the tree yielding fruit, whose 
seed was in itself, after his kind," are sending 
forth a host of sturdy offspring. The very land 
seems to be pregnant with weeds and aspiring 
young growths. But by midsummer the num- 
bers may be less. The weaker and less fortunate 
ones have perished, and the victors have waxed 
stronger thereby. The annual and half of the 
biennial species complete their course upon the 
approach of winter, and the older perennial herbs 
are becoming weak; so in the succeeding spring- 
time there is again a fierce combat for the vacant 
places. 

One of the results of this conflict is the adjust- 
ment of plants to each other. We have seen how 
the climbing plant insinuates itself in amongst the 
shrubberies and ties them together in an impene- 
trable tangle in order that it, itself, may have a 
chance to live. So the low plants of the deep 
forest are such as have been plastic enough to 
adapt themselves to the damp shades. Thus 
plants have developed companionships or diver- 



FIXATION OF VARIATIONS. 31 

gences in characters, by means of which, under 
the stress of circumstances, they are able to live 
together. Plants have adapted themselves to 
other plants as truly as they have adapted them- 
selves to soil or climate ; and if these latter en- 
vironments are ever the sources or causes of 
variation, then the first must be also. I must 
look upon the struggle for existence, therefore, 
as itself a cause of individual differences, since 
we know that any continued pressure from with- 
out awakens an adaptive response in the form of 
the vegetable organism. 

III. The Choice and Fixation of Varia- 
tions. 

We have now seen that every living object is 
unlike every other. In plants, even every branch 
is unlike any other branch. We have endeav- 
ored to discover some of the causes of these uni- 
versal differences. We have found that they 
are intimately associated with the welfare of the 
type or species, inasmuch as they appear, for 
the most part, to be the means of fitting the 
plant to live in the conditions in which it is 
placed. But we have also seen that there are 
more individuals than can find a place to live. 
How, then, does nature choose the best from the 
poorest, and, having chosen them, how does she 



32 FACT AND PHILOSOPHY OF VARIATION. 

endeavor to fix them, or to make them more or 
less stable ? 

" This preservation of favorable individual dif- 
ferences and variations, and the destruction of 
those which are injurious, I have called Natural 
Selection or the Survival of the Fittest." This 
is the philosophy which was propounded by Dar- 
win, and which will carry his name to the last 
generation of men. It looks simple enough. 
Those forms which are best fitted to live, do live, 
because they crowd out the others. Yet, this 
simple principle of natural selection 'was the first 
explanation of the process of evolution which 
seemed to be capable of interpreting the complex 
phenomena of the forms of organic life. For a 
time, this philosophy was thought to be the one 
fundamental motive of the evolution or progres- 
sion of life, but we are now convinced that there_ 
are other motives or forces at work ; but it seems j 
to be indisputable that natural selection is the 
chief force underlying the evolution of plants^J 
and it is the only one with which the person who 
desires to breed plants need intimately concern 
himself. 

We must now determine what a variety is. This 
is a vexed question, and one which seems never to 
be capable of an answer which is satisfactory to 
the gardener. Time and again, some person has 
introduced what he considered to be a distinct new 



WHAT IS A VARIETY? 33 

variety, only to find that other horticulturists dis- 
pute him and declare that it is only some old vari- 
ety renamed. And yet the introducer knows that 
he has not renamed an old variety, but that he has 
simply propagated a form which appeared or origi- 
nated upon his own grounds. 

Now, let us see. Nature starts out with the 
individual to make a new form. Every individual 
is unlike every other one. When the individual 
differences are so well marked that we can readily 
describe and distinguish them, and so permanent 
that they pass down nearly intact to a few genera- 
tions, we say that Ave have a variety. If the differ- 
ences are still more marked, we say that we have a 
species. Where the variety ends and the species 
begins it may be utterly impossible to determine ; 
so we mark off at a certain point and say, arbi- 
trarily, that this much is variety and that much 
is species. Asa Gray once said to me that " species 
are judgments." Now, if there is no hard and 
fast line between the variety and the species, so 
there is none between the individual and the vari- 
ety ; for a variety is only the family of descendants 
from some one individual. That is, the idea of 
variety or species rests upon difference, but just 
how much difference shall constitute one grade or 
another is a matter of individual opinion. So, 
when two gardeners cannot agree as to whether a 
given introduction is a new variety or not, they 



34 FACT AND PHILOSOPHY OF VARIATION. 

are having just the same difficulty that two botan- 
ists have when they cannot decide whether two 
plants are two species or one. 

It is apparent, then, that every individual plant 
is a distinct variety, only that the differences be- 
tween it and other individuals may be so slight 
that they have no practical utility and cannot be 
described and recorded. Just as soon as an indi- 
vidual plant has characters so unlike its kin that 
it has some commercial value, then the plant will 
be increased by cuttings or grafts or seeds, the 
brood of offspring will be given a name, and a new 
variety is born. 

Individuals with the same general features may 
appear simultaneously in two or more places, and 
two or more men may propagate, name, and intro- 
duce them. When they are all brought together 
and compared, it will be said that they are all the 
same variety, that, according to the rules of nomen- 
clature, the brood which chanced to be named first 
must " stand "or be held to be the type of the 
variety, and that the other names , must become 
synonyms. Yet some person may discover minor 
differences in them and demand that the varieties 
be kept distinct. So the see-saw goes on — a vari- 
ety is a variety so long as it answers some purpose 
in use or trade, and it is not a variety when it is so 
much like some other variety that it has no merit 
which the other does not possess. 



WHAT IS A VARIETY? 35 

As soon as a plant appears with some feature 
which is more desirable than anything which has 
preceded it, therefore, it may be made the begin- 
ning of a new variety. Man chooses it, and then 
propagates it. This is human selection. If nat- 
ure did the same, it would be natural selection. 

Now, how does nature preserve or fix this type ? 
She does not preserve it ! She simply chooses it 
as a beginning and gradually modifies it and shapes 
it into the form which she needs. She has no per- 
manent forms. There is a general onward pro- 
gression of every type either towards other types 
or towards extinction. We have seen that nature 
is constantly choosing and selecting. If she selects 
an individual for the beginning of a race, then 
she selects just as keenly from every offspring of 
that individual, and so on to the end of time. The 
process never stops. So nature fixes her forms by 
keeping them moving, growing, constantly develop- 
ing farther away from their beginnings. 

Now, man does the same thing. A plant in a 
cabbage row pleases him. It has a solid, small 
head and stout stem. He stores it away for seed. 
Amongst the offspring, perhaps fifty per cent are 
as good as the parent. These are saved. So the 
process goes on, from season to season. In four 
or five generations of plants, he finds that ninety 
per cent of the seeds "come true." Then he 
names it and introduces it. It is well advertised 



36 FACT AND PHILOSOPHY OF VARIATION. 

in the seed catalogues. Many people buy the 
seeds. Some of these persons will grow their 
own seed, and every one of them has a different 
ideal in mind when selecting the seed parents. 
So, in the course of a few years, it is found that 
there are really several more or less different 
forms going under the same name. Some person 
may observe this difference and legitimately in- 
troduce one or more of the forms as distinct 
varieties. Some other person, however, who has 
known the history of the stock and who is not 
aware that varieties pass into other forms, objects 
to the new names and declares that the introducer 
is imposing upon the public. 

This is the history of ninety-nine out of every 
hundred varieties which are habitually propa- 
gated by seeds, like the kitchen-garden vege- 
tables and the annual flowers. Some peculiar 
individual, appearing we know not why, is dis- 
covered, and seeds are saved and selection — 
perhaps unconscious selection — begins. After 
a time the variety is broken up into several, or 
else, if it varies only slightly into divergent 
forms, the whole body or generations of the 
variety move onward, gradually departing from 
the initial type until it is no longer the same, 
although it may still bear the same name. The 
life of seed-varieties, in their pure and original 
form, is very short. Even the best of them are 



THE PASSING OF VARIETIES. 37 

usually measured by one or two decades. They 
run out or pass out by variation, into other forms. 
The Trophy tomato is not the Trophy tomato 
which was introduced over twenty years ago, 
although it bears the old name and is a direct 
descendant of the first stock. 

In plants multiplied by buds — that is, by bud- 
ding, grafting, cuttings, tubers, and the like — 
there is less variation in the offspring than in 
those propagated by seeds. Yet we have seen 
that no two Baldwin apple trees — all of which 
are but divisions, more or less remote, of the one 
original tree — are alike, and now and then one 
branch of a fruit tree may " sport," or develop a 
strange bud-variety. We know, too, that the 
same variety of fruit tree takes on different 
characters in different geographical regions, so 
that the Greening apple is no longer the Green- 
ing of Rhode Island in the West and South. So, 
it is apparent that even when we divide a plant 
into many parts and distribute the members far 
and wide, and when there is no occasion for con- 
cerning ourselves with fixing the type, — even 
here there is variation. In some cases, particu- 
larly in those in which we multiply the plant by 
dividing abnormally developed parts, there is a 
tendency to scatter or to vary in many directions, 
and also a tendency to run out by degeneration. 
This is admirably true of the potato, varieties of 



38 FACT AND PHILOSOPHY OF VARIATION. 

which, in ten years or less, become so mixed in 
their characters, through rapid variation and de- 
terioration, that we must return to seedling pro- 
ductions for a new start. 

Man is only rarely the direct means of originat- 
ing variations. He finds them amongst the normal 
plants of the field and garden. His skill and 
science are exercised in the selection and so-called 
breeding of the offspring, more than in the original 
genesis of the new form. It is usually only in those 
plants which he multiplies by simple division that 
he gains much direct profit by crossing or hybridiz- 
ing. It is the slow and patient care and selection, 
day by day, which permanently ameliorate and 
improve the vegetable world. Nature starts the 
work ; man may complete it. 

It is now generally believed that species in 
nature sometimes originate suddenly, by means 
of " leaps." In fact, the recent De Vriesian view 
is that real species so originate, and the steps 
whereby a new species comes into existence are 
called mutations (see Lecture IV.). However 
this may be, it is nevertheless true that these mu- 
tations are yet beyond the power of man directly 
to produce. Selection is still a powerful agent 
with which to ameliorate domestic plants. 



LECTURE II. 

THE PHILOSOPHY OF THE CROSSING OF PLANTS, 
CONSIDERED IN REFERENCE TO THEIR IMPROVE- 
MENT UNDER CULTIVATION. 

I. The Struggle for Life. 

It is now understood that the specific forms or 
groups of plants have been determined largely by 
the survival of the fittest in a long and severe 
struggle for existence. The proof that this strug- 
gle everywhere exists becomes evident upon a 
moment's reflection. We know that all organisms 
are eminently variable. In fact, no two plants or 
animals in the world are exactly alike. We also 
know that very few of the whole number of seeds 
which are produced in any area ever grow into 
plants. If all the seeds produced by the elms 
upon Boston Common in any fruitful year were to 
grow into trees, this city would become a forest as 
a result. If all the seeds of the rarest orchid in 
our woods were to grow, in a few generations of 
plants even our farms would be overrun. If all 
the rabbits which are born were to reach old age, 
and all their offspring were to do the same, in less 
than ten years every vestige of herbage would be 

39 



40 PHILOSOPHY OF CROSSING PLANTS. 

swept from the country, and our farms would 
become barren. There is, then, a wonderful latent 
potency in these species ; but the same may be 
said of every species of plant and animal, even of 
man himself. If one species of plant would over- 
run and usurp the land if it increased to the full 
extent of its possibilities, what would be the result 
if each of the two thousand and sixty-one plants 
known to inhabit Middlesex County were to do the 
same ? And then fancy the result if each of the 
animals, from rabbits and mice to frogs and leeches, 
were to increase without check ! The plagues of 
Egypt would be insignificant in the comparison ! 

The fact is, the world is not big enough to hold 
the possible first offspring of the plants and ani- 
mals at this moment living upon it. Struggle for 
existence, then, is inevitable, and it must be severe. 
It follows as a necessity that those seeds grow or 
those plants live which are best fitted to grow and 
live, or which are fortunate enough to find a con- 
genial foothold. It would appear, at first thought, 
that much depends upon the accident of falling 
into a congenial place, or one unoccupied by other 
plants or animals ; but, inasmuch as scores of 
plants are contending for every unoccupied place, 
it follows that everywhere only the fittest can 
germinate or grow. In the great majority of cases, 
plants grow in a certain place because they are 
better fitted to grow there, to hold their own, than 






STRUGGLE FOR EXISTENCE. 41 

any other plants are ; and the instances are rare in 
which a plant is so fortunate as to find an un- 
occupied place. We are apt to think that plants 
chance to grow where we find them, but the chance 
is determined by law, and therefore is not chance. 

Much of the capability of a plant to persist 
under all this struggle depends, therefore, upon 
how much it varies ; for the more it varies the 
more likely it is to find places of least struggle. 
It grows under various conditions, — in sun and 
shade, in sand and clay, by the sea-shore or upon 
the hills, in the humidity of the forest or the 
aridity of the plain. In some directions it very 
likely finds less struggle than in others, and in 
these directions it expands itself, multiplies, and 
gradually dies out in other directions. So it 
happens that it tends to take on new forms, or to 
undergo an evolution. In the meantime, all the 
intermediate forms, which are at best only indif- 
ferently adapted to their conditions, tend to dis- 
appear. In other words, gaps appear which we 
call " missing links." The weak links break and 
fall away, and what was once a chain becomes a se- 
ries of rings. So the " missing links " are amongst 
the best proofs of evolution. 

The question now arises as to the cause of these 
numerous variations in animals and plants. Why 
are no two individuals in nature exactly alike? 
The question is exceedingly difficult to answer. 



42 PHILOSOPHY OF CROSSING PLANTS. 



It was once said that plants vary because it is 
their nature to vary ; that variation is a necessary 
function, as much as growth or fructification. 
This really removes the question beyond the reach 
of philosophy ; and direct observation leads us to 
think that some variation, at least, is due to ex- 
ternal circumstances. (See Lecture I.) We are 
now looking for the cause of variation as a part of 
the scheme of evolution ; and we are wondering if 
the varied surroundings, or, as Darwin put it, the 
" changed conditions of life," may not actually 
induce variability. This conclusion would seem 
to follow from the fact of the severe and universal 
struggle in nature whereby plants are constantly 
forced into new and strange conditions. But there 
is undoubtedly much variation which has sprung 
from more remote causes, one of which it is my 
purpose to discuss here. 

II. The Division of Labor. 

In the lowest animals and plants — which are 
simply single cells — the species multiplies by 
means of simple division or by budding. One in- 
dividual, of itself, becomes two, and the two are 
therefore recasts of the one. But, as organisms 
multiplied and conditions became more complex, 
that is, as struggle increased, there came a differen- 
tiation in the parts of the individual, so that one 






DIVISION OF LABOR. 43 

cell or one cluster of cells performed one labor 
and other cells performed other labor; and this 
tendency resulted in the development of organs. 
Simple division, therefore, might no longer repro- 
duce the whole complex individual ; and, as all 
organs are necessary to the existence of life, the 
organism may die if it is divided. Along with 
this specialization came the differentiation into 
sex ; and sex clearly has two offices : to hand over, 
by some mysterious process, the complex organ- 
ization of the parent to the offspring, and also to 
unite the essential characters or tendencies of two 
beings into one. The second office is manifestly 
the greater, for, as it unites two organizations into 
one, it insures that the offspring is somewhat un- 
like either parent, and is therefore better fitted to 
seize upon any place or condition new to its kind. 
And as the generations increase, the tendency 
to variation in the offspring may be constantly 
greater, because the impressions of a greater num- 
ber of ancestors are transmitted to it. I have said 
that this office of sex to induce variation is more 
important than the mere fact of reproduction of a 
complex organization ; for it must be borne in 
mind that the complexity of organization is itself 
a variation and adaptation made necessary by the 
increasing struggle for existence. 

If, therefore, the philosophy of sex is to promote 
variation by the union of different individuals, it 



44 PHILOSOPHY OF CROSSING PLANTS. 

must follow that the greatest variation must come 
from parents considerably unlike each other in 
their minor characters. Thus it comes that in- 
breeding tends to weaken a type, and cross-breeding 
tends to strengthen it. And at this point we meet 
the particular subject which I am to present to 
you. I have introduced you to this preliminary 
sketch because I contend that we can understand 
crossing only as we make it a part of the general 
philosophy of nature. There are the vaguest 
notions concerning the possibilities of crossing, 
some of which I hope to correct by presenting the 
subject in its relations to the general aspects of 
the vegetable world. 

We are now prepared to understand that crossing 
is good for the species, because it constantly revi- 
talizes offspring with the strongest traits of the 
parents, and ever presents new combinations which 
enable the individuals to stand a better chance of 
securing a place in the polity of nature. The fur- 
ther discussions of the subject are such as have to 
do with the extent to which crossing is possible and 
advisable, and the general results of the operation. 

III. The Limits of Crossing. 

If crossing is good for the species, which philoso- 
phy and direct experiment abundantly show, it is 
necessary at once to find out to what extent it can 



LIMITS OF CROSSING. 45 

be carried. Does the good increase in proportion 
as the cross becomes more violent, or as the parents 
are more and more unlike ? Or do we soon find a 
limit beyond which it is not profitable or even 
possible to go,- — a point at which we say that " an 
inch is as good as an ell " ? If great variability is 
good for the species in the struggle for existence, 
and if crossing induces variability because of the 
union of unlike individuals, it would seem to follow 
that the more unlike the parents are, the greater 
will be the' variation in offspring and the more the 
type will prosper ; and, carrying this thought to 
its logical conclusion, we should expect to find that 
the most closely related plants would constantly 
tend to refuse to cross, because the offspring of 
them would be little variable and therefore little 
adapted to the struggle for existence ; while the 
most widely separated plants would constantly tend 
to cross more and more, because their offspring 
would present the greatest possible degrees of dif- 
ferences. We should expect, for instance, that a 
Baldwin apple would be less likely to cross with a 
Greening than it is to cross with a peach or a gourd. 
And, if we should carry our thought a step farther, 
we should at once see that this crossing between 
different species would soon fill in all differences 
between those species, and that definite specific 
types would cease to exist. This would be pande- 
monium, and crossing would be the cause of it ! 



46 



PHILOSOPHY OF CROSSING PLANTS. 



Now, essentially this reasoning has been ad- 
vanced to combat the evolution of plants and 
animals by means of natural selection ; and this 
proposition that intermixing must constantly tend 
to obliterate all differences between plants and to 
prevent the establishment of well-marked types, 
has been called the " swamping effects of inter- 
crossing." It is exceedingly important that we 
consider this question, for it really lies at the 
foundation of the improvement of cultivated plants 
by means of crossing, as well as the persistence 
and evolution of varieties and species under wholly 
natural conditions. 

We find, however, that distinctspecie s, as a rule , 
refuse to cross ; and the first question which natu- 
rally arises is, What is the immediate cause of the 
refusal of plants to cross ? How does this refusal 
express itself? It comes about in many ways. 
The commonest cause is the positive refusal of 
a plant to allow its ovules to be impregnated by 
the pollen of another plant. The pollen will not 
" take." For instance, if we apply the pollen of a 
Hubbard squash to the flower of the common field 
pumpkin, there will simply be no result, — the 
fruit will not form. The same is true of the pear 
and the apple, the oat and the wheat, and most 
very unlike species. Or the refusal may come in 
the sterility of the cross or hybrid : the pollen may 
" take " and seeds may be formed and the seeds 



BARRIERS TO INTERCROSSING. 47 

may grow, but the plants which they produce may 
be wholly barren, sometimes even refusing to pro- 
duce flowers as well as seeds, as in the instance of 
some hybrids between the Wild Goose plum and 
the peach. Sometimes the refusal to cross is due 
to some difference in the time of blooming or some 
incompatibility in the structure of the flowers. But 
it is enough for our purpose to know that there are 
certain characters in widely dissimilar plants which 
prevent intercrossing, and that these characters are 
just as positive and just as much influenced by 
change of environment and natural selection as are 
size, color, productiveness, and other characters. 

Here. then, is the sufficient answer to the 
proposition that intercrossing must swamp all 
natural selection, and also the explanation of the 
varying and often restricted limits within which 
crossing is possible. That is. the checks to cross- 
ing have been developed through the principle 
of universal variability and natural selection, 
has been shown by Darwin and Wallace. Plants 
vary in their reproductive organs and powers just 
the same as they do in other directions : and when 
such a variation is useful it is perpetuated, and 
when hurtful it is lost. Suppose that a certain 
well-marked individual of a species should find an 
unusually good place in nature, and it should mul- 
tiply rapidly. Crosses would be made between 
»wn offspring and perhaps between those off- 



48 PHILOSOPHY OF CROSSING PLANTS. 

spring and itself in succeeding years ; and it is 
fair to suppose that some of the crosses would be 
particularly well adapted to the conditions in 
which the parent grew, and these would constantly 
tend to perpetuate themselves, while less adaptive 
forms would constantly tend to disappear. Now, 
the same thing would take place if this individual 
or its adaptive offspring were to cross with the 
main stock of the parent species ; for all the off- 
spring of such a cross which is intermediate in 
character and therefore less adapted to the new con- 
ditions would tend to disappear, and the two types 
would, as a result, become more and more fixed and 
the tendency to cross would constantly decrease. 

The refusal to cross, therefore, becomes a posi- 
tive character of separation, and the "missing 
links " which result from crossing are no more 
or no less inexplicable than the " missing links " 
due to simple selection ; or, to put the case more 
accurately, natural selection weeds out the ten- 
dency to promiscuous crossing, when it is hurtful, 
in just the same manner that it weeds out any 
other injurious tendency. It makes no difference 
in what way this tendency expresses itself, whether 
in some constitutional refusal to cross, — if such 
exists, — or in infertility of offspring, or in differ- 
ent times of blooming : all equally come under the 
power of natural selection. We are apt to look 
upon infertility as the absence of a character, a 



HYBRIDS RARELY USEFUL. 49 

sort of a negative feature which is somehow not 
the legitimate property of natural selection ; but 
such is not the case. We are perhaps led the 
more to this feeling because the word infertility 
is itself negative, and because we associate full pro- 
ductiveness with the positive attributes of plants. 
But loss of productiveness is surely no more a sub- 
ject of wonder than loss of color or size, if there is 
some corresponding gain to be accomplished. In 
fact, we see, in numerous plants which propagate 
easily by means of runners and suckers, a very low 
degree of productiveness, that is, infertility. 

Now, if this reasoning is sound, it leads us to 
conclusions quite the reverse of those held by the 
advocates of the swamping effects of intercrossing, 
and these conclusions are of the most vital impor- 
tance to every man who tills the soil. The logical 
result is simply this : the best results of crossing 
are obtained, as a rule, when the cross is made be- 
tween different individuals of the same variety, 
or at farthest, between different individuals of the 
same species. In other w T ords, hybrids — or crosses 
between species — are rarely useful in nature, and 
it follows that the more unlike the species the less 
useful will be the hybrids. This, I am aware, is 
counter to the notions of most horticulturists, and, 
if true, must entirely overthrow our common think- 
ing upon this subject. But I think that I shall be 
able to show that observation and experiment lead 



50 PHILOSOPHY OF CROSSING PLANTS. 

to the same conclusion to which our philosophy 
has brought us. 



IV. Function of the Cross. 

a. The Gradual Amelioration of the Type. 

At this point we must ask ourselves what we 
mean by "best results." I take this phrase to 
refer to those plants which are best fitted to sur- 
vive in the struggle for existence, those which are 
most vigorous or most productive or most hardy, 
or which possess any well-marked character or 
characters which distinguish them in virility from 
their fellows. We commonly associate the term 
more particularly with marked vigor and produc- 
tiveness ; these are the characters most useful in 
nature and also in cultivation, the ones which we 
oftenest desire to obtain. Another type of varia- 
tion which we constantly covet is something which 
we can call a new character, which will lead to the 
production of a new cultural variety, and we are 
always looking to this as the legitimate result of 
crossing. We have forgotten — if, indeed, we ever 
knew — that the commoner, all-pervading, more 
important function of the cross is to infuse some 
new strength or power into the offspring, to improve 
or to perpetuate an existing variety, rather than to 
create a new one. Or, if a new one is created, it 



FUNCTION OF THE CROSS. 51 

comes from the gradual passing of one into another, 
an inferior variety into a good one, a good one into 
a superlative one. So nature employs crossing in 
a process of slow or gradual improvement, one step 
leading to another, and not in any bold or sudden 
creation of new forms. And there is evidence to 
show that something akin to this must be done to 
secure the best and most permanent results under 
cultivation. The notion is somehow firmly rooted 
in the popular mind that new varieties can be pro- 
duced with the greatest ease by crossing parents of 
given attributes. There is something captivating 
about the notion. It smacks of a somewhat magic 
power which man evokes as he passes his wand 
over the untamed forces of nature. But the wand 
is often only a gilded stick, and is apt to serve no 
better purpose than the drum major's pretentious 
baton ? 

Let me say further that crossing alone can 
accomplish comparatively little. The chief power 
in the evolution or progression of plants appears 
to be selection, or, as Darwin puts it, the law of 
"preservation of favorable individual differences 
and variations, and the destruction of those which 
are injurious." Selection is the force which aug- 
ments, develops, and fixes types. Man must not 
only practice a judicious selection of parents from 
which the cross is to come, which is in reality but 
the exercise of a choice, but he must constantly 



52 PHILOSOPHY OF CROSSING PLANTS. 

select the best from among the crosses, in order to 
maintain a high degree of usefulness and to make 
any advancement ; and it sometimes happens that 
the selection is much more important to the culti- 
vator than the crossing. I do not wish to discour- 
age the crossing of plants, but I do desire to dispel 
the charm which too often hangs about it. 

Further discussion of this subject naturally falls 
under two heads : the improvement of existing 
types or varieties by means of crossing, and the 
summary production of new varieties. I have 
already stated that the former office is the more 
important one, and the proposition is easy of proof. 
It is the chief use which nature makes of crossing, 
— to strengthen the type. Think, for instance, of 
the great rarity of hybrids or pronounced crosses 
in nature. No doubt all the authentic cases on 
record could be entered in one or two volumes, but 
a list of all the individual plants of the world 
could not be compressed into ten thousand volumes. 
There are a few genera, in which the species are 
not well defined or in which some character of 
inflorescence favors promiscuous crossing, in which 
hybrids are conspicuous ; but even here the num- 
ber of individual hybrids is very small in compari- 
son to the whole number of individuals. That is, 
the hybrids are rare, while the parents may be 
common. This is well illustrated even in the 
willows and oaks, in which, perhaps, hybrids are 



RARITY OF HYBRIDS. 53 

better known than in any other American plants. 
The great genus carex or seclge, which occurs in 
great numbers and many species in almost every 
locality in New England, and in which the species 
are particularly adapted to intercrossing by the 
character of their inflorescence, furnishes but few 
undoubted hybrids. Among one hundred and 
eighty-five species and prominent varieties inhabit- 
ing the northeastern states, there are only eleven 
hybrids recorded, and all of them are rare or local, 
some of them having been collected but once. 
Species of carex of remarkable similarity may grow 
side by side for years, even intertangled in the 
same clump, and yet produce no hybrid. These 
instances prove that nature avoids hybridization, 
— a conclusion at which we have already arrived 
from philosophical considerations. And we have 
reason to infer the same conclusion from the fact 
that flowers of different species are so constructed 
as not to invite intercrossing. But, on the other 
hand, the fact that all higher plants habitually 
propagate by means of seeds, which is far the most 
expensive to the plant of all methods of propa- 
gation, while at the same time most flowers are so 
constructed as to prevent self-fertilization, proves 
that some corresponding good must come from 
crossing within the limits of the species or variety ; 
and there are purely philosophical reasons, as we 
have seen, which warrant a similar conclusion. 



54 PHILOSOPHY OF CROSSING PLANTS. 

But experiment has given us more direct proof of 
our propositions, and we shall now turn our atten- 
tion to the garden. 

Darwin was the first to show that crossing within 
the limits of the species or variety results in a con- 
stant revitalizing of the offspring, and that this is 
the particular ultimate function of cross-fertiliza- 
tion. Kolreuter, Sprengel, Knight, and others had 
observed many, if, indeed, not all, the facts obtained 
by Darwin ; but they had not generalized upon 
them broadly, and did not conceive their relation 
to the complex life of the vegetable world. Dar- 
win's results are, concisely, these ; self-fertilization 
tends to weaken the offspring;* crossing between 
different plants of the same variety gives stronger 
and more productive offspring than arises from 
self-fertilization ; crossing between stocks of the 
same variety grown in different places or under dif- 
ferent conditions gives better offspring than cross- 
ing between different plants grown in the same 
place or under similar conditions ; and his re- 
searches have also shown that, as a rule, flowers 
are so constructed as to favor cross-fertilization. 
In short, he found, as he expressed it, that " nature 
abhors perpetual self-fertilization." Some of his 
particular results, although often quoted, will be 
useful in fixing these facts in our minds. Plants 
from crossed seeds of morning-glory exceeded in 
height those from self-fertilized seeds as 100 exceeds 



INCREASED VIGOR OF CROSS-BREEDS. 55 

76, in the first generation. Some flowers from these 
plants were self-pollinated and some were crossed, 
and in this second generation the crossed plants 
were to the uncrossed as 100 is to 79 ; the opera- 
tion was again repeated, and in the third generation 
the figures stand 100 to 68 ; fourth generation, the 
plants having been grown in midwinter, when none 
of them did well, 100 to 86 ; fifth generation, 100 
to 75 ; sixth generation, 100 to 72 ; seventh genera- 
tion, 100 to 81 ; eighth generation, 100 to 85 ; ninth 
generation, 100 to 79 ; tenth generation, 100 to 
54. The average total gain in height of the 
crossed over the uncrossed was as 100 to 77, or 
about 30 per cent. There was a corresponding 
gain in fertility, or the number of seeds and seed- 
pods produced. Yet, striking as the results are, 
they were produced by simply crossing between 
plants grown near together, and under what would 
ordinarily be called uniform conditions. In order 
to determine the influence of crossing with fresh 
stock, plants of the same variety were obtained 
from another garden, and these were crossed with 
the ninth generation mentioned above. The off- 
spring of this cross exceeded those of the other 
crossed plants as 100 exceeds 78, in height ; as 100 
exceeds 57, in the number of seed-pods ; and as 100 
exceeds 51, in the weight of the seed-pods. In 
other words, crosses between fresh stock of the same 
variety were nearly 30 per cent more vigorous than 



56 



PHILOSOPHY OF CROSSING PLANTS. 



crosses between plants grown side by side for some 
time and over 44 per cent more vigorous than 
plants from self-fertilized seeds. On the other 
hand, experiments showed that crosses between 
different flowers upon the same plant gave actu- 
ally poorer results than offspring of self-fertilized 
flowers. It is evident, from all these figures, that 
nature desires crosses between plants, and, if pos- 
sible, between plants grown under somewhat dif- 
ferent conditions. All the results are exceedingly 
interesting and important; and there is every 
reason to believe that, as a rule, similar results can 
be obtained with all plants. 

Darwin extended his investigations to many 
plants, only a few of which need be discussed here. 
Cabbage gave pronounced results. Crossed plants 
were to self-fertilized plants in weight as 100 is 
to 37. A cross was now made between these 
crossed plants and a plant of the same variety 
from another garden, and the difference in weight 
of the resulting offspring was the difference be- 
tween 100 and 22, showing a gain of over 350 per 
cent, due to a cross with fresh stock. Crossed 
lettuce plants exceeded uncrossed in height as 
100 exceeds 82. Buckwheat gave an increase in 
weight of seeds as 100 to 82, and in height of 
plants as 100 to 69. Beets gave an increase in 
height represented by 100 and 87. Maize, when 
full grown, from crossed and uncrossed seeds, 



INCREASED VIGOR OF CROSS-BREEDS. 57 

gave the differences in height between 100 and 91. 
Canary-grass gave similar results. 

I have obtained results as well marked as these 
upon a large and what might be called a commer- 
cial scale. I raised the plants during the first 
generation of seeds from known parentage, the 
flowers from which they came having been care- 
fully pollinated by hand. In some instances the 
second generations were grown from hand-crossed 
seeds, but in other cases the second generations 
were grown from seeds simply selected from the 
first-year patches. As the experiments have been 
made in the field and upon a somewhat extensive 
scale, it was not possible to accurately measure 
the plants and the fruits from individuals in all 
cases ; but the results have been so marked as to 
admit of no doubt as to their character. In 1889 
several hand-crosses were made among egg-plants. 
Three fruits matured, and the seeds from them 
were grown in 1890. Some two hundred plants 
were grown, and they were characterized through- 
out the season by great sturdiness and vigor of 
growth. They grew more erect and taller than 
other plants near by grown from commercial seeds. 
They were the finest plants which I had ever seen. 
It was impossible to determine productiveness, 
from the fact that our seasons are too short for 
egg-plants, and only the earliest flowers, in the 
large varieties, perfect their fruit, and the plant 



58 PHILOSOPHY OF CROSSING PLANTS. 

blooms continuously through the season. In order 
to determine how much a plant will bear, it must 
be grown until it ceases to bloom. When frost 
came, I could see little difference in productive- 
ness between these crossed plants and commercial 
plants. A dozen fruits were selected from various 
parts of this patch, and in 1891 about twenty-five 
hundred plants were grown from them. Again 
the plants were remarkably robust and healthy, 
with fine foliage, and they grew erect and tall, — 
an indication of vigor. They were also very pro- 
ductive ; but, as the cross had been made between 
unlike varieties, and the offsprings were therefore 
unlike either parent, I could not make an accurate 
comparison. But they compared well with com- 
mercial egg-plants, and I am satisfied that they 
would have shown themselves to be more produc- 
tive than common stock could they have grown a 
month or six weeks longer. Professor Munson, of 
the Maine Agricultural College, grew some of this 
crossed stock in 1891, and he told me that it was 
better than any commercial stock in his gardens. 

In extended experiments in the crossing of 
pumpkins, squashes, and gourds, carried on dur- 
ing several years, increase in productiveness due 
to crossing has been marked in many instances. 
Marked increase in productiveness has been ob- 
tained from tomato crosses, even when no other 
results of crossing could be seen. 



BENEFITS FROM CHANGE OF SEED. 59 

b. Change of Seed and Crossing. 

Bearing in mind these good influences of cross- 
ing, let us recall another series of facts following 
the simple change of seed. Almost every farmer 
and gardener at the present day feel that an 
occasional change of seed results in better crops, 
and there are definite records to show that such 
is often the case. In fact, I am convinced that 
much of the rapid improvement in fruits and vege- 
tables in recent years is due to the practice of 
buying plants and seeds so largely of dealers, by 
means of which the stock is often changed. Even 
a slight change, as between farms or neighboring 
villages, sometimes produces marked results, such 
as more vigorous plants and often more fruitful 
ones. We must not suppose, however, that be- 
cause a small change gives a good result, a violent 
or very pronounced change gives a better one. 
There are many facts on record to show that great 
changes often profoundly influence plants, and 
when such influence results in lessened vigor or 
lessened productiveness we call it an injurious one. 
Now, this injurious influence may result even 
when all the conditions in the new place are 
favorable to the health and development of the 
plant ; it is an influence which is wholly indepen- 
dent, so far as we can see, of any condition which 
interferes injuriously with the simple processes of 



60 PHILOSOPHY OF CROSSING PLANTS. 

growth. Seeds of a native physalis or husk-tomato 
were sent to me from Paraguay in 1889 by Dr. 
Thomas Morong, then travelling in that country. 
I grew it from cuttings in the house and out of 
doors, and for two generations was unable to make 
it set fruit, even though the flowers were hand-pol- 
linated; yet the plants were healthy and grew vig- 
orously. The third cutting-generation grown put 
of doors set fruit freely. This is an instance of 
the fact that very great changes of conditions may 
injuriously affect the plant, and an equally good 
illustration of the power to overcome these condi- 
tions. Now, there is great similarity between the 
effects of slight and violent changes of conditions 
and small and violent degrees of crossing, as both 
Darwin and Wallace have pointed out, and it is 
pertinent to this discussion to endeavor to dis- 
cover why this similarity exists. 

It is well proved that crossing is good for the 
resulting offspring, because the differences be- 
tween the parents carry over new combinations 
of characters or at least new powers into the 
crosses. It is a process of revitalization, and the 
more different the stocks in desirable characters 
within the limits of the variety, the greater is 
the revitalization; and frequently the good is of 
a more positive kind, resulting in pronounced 
characters which may serve as the basis for new 
varieties. In the cross, therefore, a new combina- 



BENEFITS FROM CHANGE OF SEED. 61 

tion of characters or a new power fit it to live 
better than its parents in the conditions under 
which they lived. 

In the case of change of stock we find just the 
reverse, which, however, amounts to the same 
thing, — that the same characters or powers fit the 
plant to live better in conditions new to it than 
plants which have long lived in those conditions. 
In either case, the good comes from the fitting 
together of new characters or powers and new 
environments. Plants which live during many 
generations in one place become accustomed to the 
place, thoroughly fitted into its conditions, and are 
in what Mr. Spencer calls a state of equilibrium. 
When either plant or conditions change, new ad- 
justments must take place ; and the plant may find 
an opportunity to take advantage, to expand in 
some direction in which it has before been held 
back ; for plants always possess greater power 
than they are able to express. " These rhythmical 
actions or functions [of the organism]," writes 
Spencer, "and the various compound rhythms 
resulting from their combinations, are in such 
adjustment as to balance the actions to which 
the organism is subject. There is a constant or 
periodic genesis of forces which, in their kinds, 
amounts, and directions, suffice to antagonize the 
forces which the organism has constantly or peri- 
odically to bear. If, then, there exists this state 



62 PHILOSOPHY OF CROSSING PLANTS. 

of moving equilibrium among a definite set oJ 
internal actions, exposed to a definite set of ex- 
ternal actions, what must result if any of the 
external actions are changed ? Of course there is 
no longer an equilibrium. Some force which the 
organism habitually generates is too great or too 
small to balance some incident force ; and there 
arises a residuary force exerted by the environ- 
ment on the organism, or by the organism on the 
environment. This residuary force, this unbal- 
anced force, of necessity expends itself in produc- 
ing some change of state in the organism." 

The good results, therefore, are processes of 
adaptation, and when adaptation is perfectly com- 
plete the plant may have gained no permanent 
advantage over its former condition, and new 
crossing or another change may be necessaiy ; yet 
there is often a permanent gain, as when a plant 
becomes visibly modified by change to another cli- 
mate. Now, this adaptive change may express 
itself in two ways : either by some direct influence 
upon the stature, vigor, or other general character, 
or indirectly upon the reproductive powers, by 
which some new influence is carried to the off- 
spring. If the direct influences become heredi- 
tary, as observation seems to show may sometimes 
occur, the two directions of modification may 
amount, ultimately, to the same thing. 

For the purposes of this discussion it is enough 



CHANGE OF STOCK AND CROSSING. 63 

to know that crossing within the variety and 
change of stock within ordinary bounds are bene- 
ficial, that the results in the two cases seem to 
flow from essentially the same causes, and that 
crossing and change of stock combined give much 
better results than either one alone ; and this 
benefit is expressed more in increased yield and 
vigor than in novel and striking variations. These 
processes are much more important than airy mere 
groping after new varieties, as I have already said; 
not only because they are surer, but because they 
are universal and necessary means of maintaining 
and improving both wild and cultivated plants. 
Even after one succeeds in securing and fixing 
a new variety, he must employ these means to a 
greater or less extent to maintain fertility and 
vigor, and to keep the variety true to its type. 
In the case of some garden crops, in which many 
seeds are produced in each fruit and in which 
the operation of pollination is easy, actual hand- 
crossing from new stock now and then may be 
found to be profitable. But in most cases the 
operation can be left to nature, if the new stock 
is planted among the old. Upon this point Dar- 
win expressed himself as follows : " It is a common 
practice with horticulturists to obtain seeds from 
another place having a very different soil, so as to 
avoid raising plants for a long succession of gen- 
erations under the same conditions ; but with all 



64 PHILOSOPHY OF CROSSING PLANTS. 

the species which freely intercross by the aid of 
insects or the wind, it would be an incomparably 
better plan to obtain seeds of the required variety, 
which had been raised for some generations under 
as different conditions as possible, and sow them 
in alternate rows with seeds matured in the old 
garden. The two stocks would then intercross, 
with a thorough blending of their whole organi- 
zations, and with no loss of purity to the variety, 
and this would yield far more favorable results 
than a mere change of seed." 

c. TJie Outright Production of Neiv Varieties. 

But you are waiting for a discussion of the 
second of the great features of crossing, — the sum- 
mary production of new varieties» This is the sub- 
ject which is almost universally associated with 
crossing in the popular mind, and even among 
horticulturists themselves. It is the commonest 
notion that the desirable characters of given 
parents can be definitely combined in a pronounced 
cross or hybrid. There are two or three philo- 
sophical reasons which somewhat oppose this doc- 
trine, and which we will do well to consider at the 
outset. In the first place, nature is opposed to 
hybrids, for species have been bred away from each 
other in the ability to cross. If, therefore, there 
is no advantage for nature to hybridize, we may 



PRODUCTION OF NOVELTIES. 65 

suppose that there would be little advantage for 
man to do so ; and there would be no advantage 
for man did he not place the plant under conditions 
different from nature, or desire a different set of 
characters. We have seen that nature's chief 
barriers to hybridization are total refusal of species 
to unite, and entire or comparative seedlessness 
of offspring. We can overcome the refusal to 
cross in many cases by bringing the plant under 
cultivation; for the character of the species be- 
comes so changed by the wholly new conditions 
that its former antipathies may be overpowered. 
Yet it is doubtful if such a plant will ever acquire 
a complete willingness to cross. In like manner 
we can overcome in a measure the comparative 
seedlessness of hybrids, but it is very doubtful 
whether we can ever make such hybrids com- 
pletely fruitful. It would appear, therefore, 
on theoretical grounds, that in plants in which 
seeds are the part sought, no permanent prac- 
tical good can be expected, as a rule, from hy- 
bridization. 1 

It is evident that species which have been 
differentiated or bred away from each other in 
a given locality will have more opposed qualities 
or powers than similar species which have arisen 
quite independently in places remote from each 

1 See definition of hybrids, crosses, and other terms in the 
Glossary. 



06 PHILOSOPHY OF CROSSTXG PLANTS. 

other. In the one case the species have likely 
struggled with each other until each one has at- 
tained to a degree of divergence which allows it 
to persist ; while in the other case there has been 
no struggle between the species, but similar con- 
ditions have brought about similar results. These 
similar species which appear independently of 
each other in different places are called representa- 
tive species. Islands remote from each other but 
similarly situated with reference to climate very 
often contain representative species ; and the same 
may be said of other regions much like each other, 
as eastern North America and Japan. Now, it 
follows that, if representative species are less 
opposed than others, they are more likely to 
hybridize with good results ; and this fact is re^ 
markably well illustrated in the Kieffer and allied 
pears, which are hybrids between representative 
species of Europe and Japan ; and I am inclined 
to think that the same may be found to be true 
of the common or European apple and the wild 
crab of the Mississippi valley. Various crabs of 
the Soulard type, which I once thought to con- 
stitute a distinct species, appear upon further study 
to be hybrids. We will also recall that the hybrid 
grapes which have so far proved most valuable are 
those obtained by Rogers between the American 
Vitis Labrusca and the European wine grape ; and 
that the attempts of Haskell and others to hybrid- 



INSTABILITY OF HYBRIDS. 67 

ize associated species of native grapes have given, 
at best, only indifferent results. To these good 
results from hybrids of fruit trees and vines I 
shall revert presently. 

Another theoretical point, which is borne out 
by practice, is the conclusion that, because of the 
great differences and lack of affinity between par- 
ents, pronounced hybrid offsprings are unstable. 
This is one of the greatest difficulties in the way 
of the summary production of new varieties by 
means of hybridization. It would appear, also, 
that, because of the unlikeness of parents, hybrid 
offspring must be exceedingly variable ; but, as 
a matter of fact, in many instances the parents 
are so pronouncedly different that the hybrids 
represent a distinct type by themselves, or else 
they approach very nearly to the characters of 
one of the parents. There are, to be sure, many 
instances of exceedingly variable hybrid offspring, 
but they are usually the offspring of variable par- 
ents. In other words, variability in offspring 
appears to follow rather as a result of variability 
in parents than as a result of mere unlikeness 
of characters. But the instability of hybrid off- 
spring when propagated by seed is notorious. 
Wallace writes that "the effect of occasional 
crosses often results in a great amount of varia- 
tion, but it also leads to instabilit}^ of character, 
and is therefore very little employed in the 



68 PHILOSOPHY OF CROSSING PLANTS. 

production of fixed and well-marked races." I 
may remark again that, because of the unequal 
and unknown powers of the parents, we can never 
predict what characters will appear in the hybrids. 
This fact was well expressed by Lindley a half 
century ago, in the phrase, " Hybridizing is a 
game of chance played between man and plants." 

V. Characteristics of Crosses. 

Bearing these fundamental propositions in mind, 
let us pursue the subject somewhat in detail. 
We shall find that the characters of hybrids, 
as compared with the characters of simple crosses 
between stocks of the same variety, are ambiguous, 
negative, and often prejudicial. The fullest dis- 
cussion of hybrids has been made by Focke (see 
Lecture IV.), and he lays down the five following 
propositions concerning the character of hybrid 
offspring : — 

1. " All individuals which have come from the 
crossing of two pure species or races, when pro- 
duced and grown under like conditions, are 
usually exactly like each other, or at least scarcely 
more different from each other than plants of the 
same species are." This proposition, although 
perhaps true in the main, appears to be too 
broadly and positively stated. . 

2. " The characters of hybrids may be different 



HYBRIDS AND CROSS-BREEDS. 69 

from the characters of the parents. The hybrids 
differ most in size and vigor and in their sexual 
powers." 

3. " Hybrids are distinguished from their par- 
ents by their powers of vegetation or growth. 
Hybrids between very different species are often 
weak, especially when young, so that it is difficult 
to raise them. On the other hand, cross-breeds 
are, as a rule, uncommonly vigorous ; they are dis- 
tinguished mostly by size, rapidity of growth, early 
flowering, productiveness, longer life, stronger 
reproductive power, unusual size of some special 
organs, and similar characteristics." 

4. " Hybrids produce a less amount of pollen 
and fewer seeds than their parents, and they 
often produce none. In cross-breeds this weaken- 
ing of the reproductive powers does not occur. 
The flowers of sterile or nearly sterile hybrids 
usually remain fresh a long time." 

5. M Malformations and odd forms are apt to 
appear in hybrids, especially in the flowers." 

Some of the relations between hybridization 
and crossing within narrow limits are stated as 
follows by Darwin : " It is an extraordinary fact 
that with many species flowers fertilized with 
their own pollen are either absolutely or in some 
degree sterile ; if fertilized with pollen from 
another flower on the same plant, they are some- 
times, though rarely, a little more fertile ; if 



70 PHILOSOPHY OF CROSSING PLANTS. 

fertilized with pollen from another individual 
or variety of the same species, they are fully 
fertile ; but if with pollen from a distinct species, 
they are sterile in all possible degrees, until utter 
sterility is reached. We thus have a long series 
with absolute sterility at the two ends ; at one 
end due to the sexual elements not having been 
sufficiently differentiated, and at the other end 
to their having been differentiated in too great 
a degree, or in some peculiar manner." 

The difficulties in the way of successful results 
through hybridization are, therefore, these : the 
difficulty of effecting the cross ; infertility, in- 
stability, variability, and often weakness and 
monstrosity of the hybrids ; and the absolute im- 
possibility of predicting results. The advantage 
to be derived from a successful hybridization is 
the securing of a new variety which shall combine 
in some measure the most desirable features of 
both parents ; and this advantage is often of so 
great moment that it is worth while to make re- 
peated efforts and to overlook numerous failures. 
From these theoretical considerations it is apparent 
that hybridization is essentiall} r an empirical sub- 
ject, and the results are such as fall under the 
common denomination of chance. And, as it does 
not rest upon any legitimate function in nature, 
we can understand that it will always be difficult 
to codify laws upon it. 



HYBRIDS AND BUD -PROPAGATION. 71 

Among the various characters of hybrid off- 
spring, I presume that the most prejudicial one is 
their instability, their tendency still to vary into 
new forms or to return to one or the other parent 
in succeeding generations. It is difficult to fix ! 
any particular form which we may secure in the 
first generation of hybrids. At the outset, we 
notice that this discouraging feature is manifested 
chiefly through the fact of seed-reproduction, and 
we thereby come upon what is perhaps the most 
important practical consideration in hybridization, 
— the fact that the great majority of the best / 
hybrids in cultivation are increased by bud-propa- 
gation, as cuttings, layers, suckers, buds, or grafts. 
In fact, I recall very few instances in this country 
of good undoubted hybrids which are propagated 
with practical certainty by means of seeds. You 
will recall that the genera in which hybrids are 
most common are those in which bud-propagation 
is the rule ; as begonia, pelargonium, orchids, 
gladiolus, rhododendron, roses, cannas, and the 
fruits. This simply means that it is difficult to 
fix hybrids so that they will come " true to seed,; 
and makes apparent the fact that if we desire 
hybrids we must expect to propagate them by 
means of buds. 

This is a point which appears to have been over- 
looked by those who contend that hybridization 
must necessarily swamp all results of natural se- 






72 PHILOSOPHY OF CBOSSIXG PLANTS. 

lection ; for, as comparatively few plants propagate 
habitually by means of buds, whatever hybrids 
might have appeared would have been speedily 
lost, and all the more, also, because, by the terms 
of their reasoning, the hybrids would cross with 
other and dissimilar forms, and therefore lose their 
identity as intermediates. Or, starting with the 
assumption that hybrids are intermediates, and 
would therefore obliterate specific types, we must 
conclude that they should have some marked de- 
gree of stability if they are to swamp or obliterate 
the characters of species ; but, as all hybrids tend 
to break up when propagated by seeds, it must 
follow that bud-propagation would become more 
and more common, and this is associated in nature 
with decreased seed-production. Now, seed-pro- 
duction is the legitimate function of flowers ; and 
we must concede that, as seed-production de- 
creased, floriferousness must have decreased ; and 
that, therefore, pronounced intercrossing would 
have obliterated the very organs upon which it 
depends, or have destroyed itself ! 

But I may be met by the objection that there 
is no inherent reason why hybrids should not 
become stable through seed-production by in-breed- 
ing, and I might be cited to the opinion of Darwin 
and others that in-breeding tends to fix any va- 
riety, whether it originates by crossing or other 
means. And it is a fact that in-breeding tends to 



IN-BREEDIXG OF CROSSES. 73 

fix varieties within certain limits, but those limits 
are often overpassed in the case of very pro- 
nounced crosses, whether cross-breeds or true 
hybrids. And if it is true, as all observation and 
experiments show, that sexual or reproductive 
powers of crosses are weakened as the cross be- 
comes more violent, we should expect less and less 
possibility of successful in-breeding ; for in-breed- 
ing without disastrous results is possible only with 
comparatively strong reproductive powers. As a 
matter of fact, it is found in practice that it is 
exceedingly difficult to fix pronounced hybrids by 
means of in-breeding. It sometimes happens, too, 
that the hybrid individual which we wish to per- 
petuate may be infertile with itself, as I have often 
found in the case of squashes. It is often advised 
that we cross the hybrid individual which we wish 
to fix with another like individual, or with one of 
its parents. These results are often successful, 
but oftener they are not. In the first place, it 
often happens that the hybrid individuals may be 
so diverse that no two of them are alike ; this has 
been my experience in many crosses. And, again, 
crossing with a parent may draw the hybrid back 
again to the parental form. So long ago as lasl 
century Kolreuter proved this fact upon nicotiana 
and dianthus. A hybrid between Nicotiana rus- 
tica and N. paniculata was crossed with N. pani- 
culata until it was indistinguishable from it; and 



74 PHILOSOPHY OF CROSSING PLANTS. 

it was then crossed with N. rustica until it became 
indistinguishable from that parent. Yet there is 
no other way of fixing a hybrid to be propagated 
by seeds than by in-breeding, and by constant at- 
tention to selection. Fortunately, it occasionally 
happens that a hybrid is stable, and therefore 
needs no fixing. 

In this connection I may cite some of my own 
experience in crossing egg-plants and squashes ; 
for, although the products were not true hybrids 
in the strict interpretation of the word, many of 
them were hybrids to all intents and purposes, 
because made between very unlike varieties, and 
they will serve to illustrate the difficulties of which 
I speak. Offspring of egg-plant crosses were grown 
in 1890, and upon some of the most promising 
plants some flowers were self-pollinated. But 
these self-pollinated seeds gave just as variable 
offspring in 1891, as those selected almost at 
random from the patch; and, what was worse, 
none of them reproduced the parent, or " came 
true to seed," and all further motive for in-breed- 
ing was gone. My labor, therefore, amounted to 
nothing more than my own edification. My 
experience in crossing pumpkins and squashes has 
now extended through many years ; and, although 
I have obtained about one thousand types not 
named or described, I have not yet succeeded in 
fixing one. The difficulty here is an aggravated 



EXPERIMENTS IN IN-BREEDING. 75 

one, however. The species are so exceedingly 
variable that all the hybrid individuals may be 
unlike, so that there can be no crossing between 
identical stocks ; and, if in-breeding is attempted, 
it may be found that the flowers will not in-breed. 
And the refusal to in-breed is all the more strange 
because the sexes are separated in different flowers 
upon the same plant. In other words, in my expe- 
rience, it is very difficult to get good seeds from 
squashes which are fertilized by a flower upon the 
same vine. The squashes may grow normally to 
full maturity, but be entirely hollow, or contain 
only empty seeds. In some instances the seeds 
may appear to be good, but may refuse to grow 
under the best conditions. Finally, a small number 
of flowers may give good seeds. I have many 
times observed this refusal of squashes (Cucurbita 
Pepo) to in-breed. It was first brought to my 
attention through efforts to fix certain types into 
varieties. The figures of one season's tests will 
sufficiently indicate the character of the problem. 
In 1890, one hundred and eighty-five squash flowers 
were carefully pollinated with staminate flowers 
taken from the same vine which bore the pistillate 
flowers. Only twenty-two of these produced fruit, 
and of these only seven, or less than one-third, bore 
good seeds, and in some of these the seeds were 
few. Now, these twenty-two fruits represented as 
many different varieties, so that the inability to set 



76 PHILOSOPHY OF CROSSING PLANTS. 

fruit with pollen from the same vine is not a 
peculiarity of a particular variety. The records 
of the seeds of the seven fruits in 1891 are as 
follows : — 

Fruit No. 1. — Four vines were obtained, with 
four different types, two of them being white, one 
yellow, and one black. 

Fruit No. 2. — Twenty-three vines. Fifteen 
types very unlike, twelve being white and three 
yellow. 

Fruit No. 3. — Two vines. One type of fruit 
which was almost like one of the original parents. 

Fruit No. 4. — Thirty-two vines. Six types, 
differing chiefly in size and shape. 

Fruit No. 5. — Twenty vines. Nineteen types, 
of which ten were white, eight orange, one striped, 
and all very unlike. 

Fruit No. 6. — Thirteen vines. Eleven types, 
— eight yellow, two black, one white. 

Fruit No. 1. — One vine. 

These offspring were just as variable as those 
from flowers not in-bred, and no more likely, 
apparently, to reproduce the parent. These tests 
leave me without any method of fixing a pro- 
nounced cross of squashes, and lead me to think 
that the legitimate process of origination of new 
kinds here, as, indeed, if not in general, is a more 
gradual process of selection, coupled, perhaps, with 
minor crossing. 



ATTEMPT TO FIX A CROSS. 77 

I will relate a definite attempt towards the fixa- 
tion of a squash which I had obtained from cross- 
ing. The history of it runs back to 1887, when a 
cross was effected between a summer yellow crook- 
neck and a white bush scallop squash. In 1889 
there appeared a squash of great excellence, com- 
bining the merits of summer and winter squashes 
with very attractive form, size, and color, and a 
good habit of plant. I showed the fruit to one of 
the most expert seedsmen of the country, and he 
pronounced it one of the most promising types 
which he had ever seen ; and, as he informed me 
that he had fixed squashes by breeding in and in, 
I was all the more anxious to carry out my own 
convictions in the same direction. It is needless 
to say that I was very happy over what I regarded 
as a great triumph. Of course I must have a large 
number of plants of my new variety, that I might 
select the best, both for in-breeding and for cross- 
ing similar types. So I selected the very finest 
squash, having placed it where I could admire it 
for some days, and saved every seed of it. These 
seeds were planted upon the most conspicuous 
knoll in my garden in 1890. It was soon evident 
that something was wrong. I seemed to have 
everything except my squash. One plant, how- 
ever, bore fruits almost like the parent, and upon 
this I began my attempts towards in-breeding. 
But flower after flower failed, and I soon saw that 



78 PHILOSOPHY OF CROSSING PLANTS. 

the plant was infertile with itself. Careful search 
revealed two or three other plants very like this 
one, and I then proceeded to make crosses upon it. 
I was equally confident that this method would 
succeed. When I harvested my squashes in the 
fall and took account of stock, I found that the 
seeds of my one squash had given just as many 
different types as there were plants, and I actually 
counted one hundred and ten kinds distinct enough 
to be named and recognized. Still confident, in 
1891 I planted the seeds of my few crosses, and as 
the summer days grew long and the crickets 
chirped in the meadows, I watched the expanding 
squash blossoms and wondered what they would 
bring forth. But they brought only disappoint- 
ment. Not one seed produced a squash like the 
parent. My squash had taken an unscientific 
leave of absence, and I do not know its where- 
abouts. And when the frost came and killed 
every ambitious blossom, my hope went out and 
has not yet returned ! 

Let us now recall how many undoubted hybrids 
there are, named and known, among our fruits 
and vegetables. In grapes there are the most. 
There are Rogers' hybrids, like the Agawam, 
Lindley, Wilder, Salem, and Barry; and there is 
some reason for supposing that the Delaware, 
Catawba, and other varieties are of hybrid origin. 
And many hybrids have come to notice lately 






LIST OF COMMON HYBRIDS. 79 

through the work of Munson and others. But it 
must be remembered that grapes are naturally ex- 
ceedingly variable, and the specific limits are not 
well known, and that hybridization among them 
lacks much of that definiteness which ordinarily 
attaches to the subject. In pears there is the 
KiefTer class. In apples, peaches, plums, cher- 
ries, gooseberries, and currants, there are no im- 
portant commercial hybrids. In blackberries there 
is the blackberry-dewberry class, represented by 
the Wilson Early and others. Some of the rasp- 
berries, like the Philadelphia and Shaffer, are hy- 
brids between the red and black species. Hybrids 
have been produced between the raspberry and 
blackberry by two or three persons, but they pos- 
sess no promise of economic results. Among all 
the list of garden vegetables (plants which are 
propagated by seeds) I do not know of a single 
important hybrid ; and the same is true of wheat, 
— unless the Carman wheat-rye varieties become 
prominent, — oats, the grasses, and other farm 
crops. But among ornamental plants there are 
many ; and it is a significant fact that the most 
numerous, most marked, and most successful hy- 
brids occur in the plants most carefully cultivated 
and protected, those, in other words, which are 
farthest removed from all untoward circumstances 
and an independent position. This is nowhere so 
well illustrated as in the case of cultivated orchids, 



80 PHILOSOPHY OF CROSSING PLANTS. 

in which hybridization has played no end of freaks, 
and in which, also, every individual plant is nursed 
and coddled. 1 With such plants the struggle for 
existence is reduced to its lowest terms ; for it 
must be borne in mind that, even in the garden, 
plants must fight severely for a chance to live, and 
even then only the very best can persist, or are 
even allowed to try. 

I am sure that this list of hybrids is much more 
meagre than most catalogues and trade-lists would 
have us believe, but I am sure that it is approxi- 
mately near the truth. It is, of course, equivalent 
to saying that most of the so-called hybrid fruits 
and vegetables are myths. There is everywhere a 
misconception of what a hybrid is, and how it 
comes to exist ; and yet, perhaps because of this 
indefinite knowledge, there is a wide-spread feel- 
ing that a hybrid is necessarily good, while the 
presumption is directly the opposite. The identity 
of a hybrid in the popular mind rests entirely upon 
some superficial character, and proceeds upon the 
assumption that it is necessarily intermediate be- 
tween the parents. Hence we find one of our 
popular authors asserting that, because the kohl- 
rabi bears its thickened portion midway of its stem, 
it is evidently a hybrid between the cabbage and 
turnip, which bear respectively the thickened parts 

1 Consult E. Bohnhof, " Dictionnaire des Orchid^es Hy- 
brides," Paris, 1895. 



INFLUENCE OF PARENTS. 81 

at the opposite extremities of the stem ! And then 
there are those who confound the word hybrid 
with high-bred, and who build attractive castles 
upon the unconscious error. And thus is confu- 
sion confounded ! 

But, before leaving this subject of hybridization, 
I must speak of the old yet common notion that 
there is some peculiar influence exerted by each 
sex in the parentage of hybrids ; for I shall thereby 
not only call your attention to what I believe to 
be an error, but shall also find the opportunity to 
still further illustrate the entanglements of hybri- 
dization. It was held by certain early observers, of 
whom the great Linnaeus was one, that the female 
parent determines the constitution of the hybrid, 
while the male parent gives the external attributes, 
as form, size, and color. The accumulated experi- 
ence of nearly a century and a half appears to con- 
tradict this proposition, and Focke, who has recently 
gone over the whole ground, positively declares 
that it is untrue. There are instances, to be sure, 
in which this old idea is affirmed, but there are 
others in which it is contradicted. The truth ap- 
pears to be this, — that the parent of greater 
strength or virility makes the stronger impression 
upon the hybrids, whether it is the staminate or 
pistillate parent ; and it appears to be equally 
true that it is usually impossible to determine be- 
forehand which parent is the stronger. It is cer- 



82 PHILOSOPHY OF CROSSING PLANTS. 

tain that strength does not lie in size, neither in 
the high development of any character. It appears 
to be more particularly associated with what we 
call fixity or stability of character, or the tendency J 
towards invariability. 

This has been well illustrated in my own experi- 
ments with squashes, gourds, and pumpkins. The 
common little pear-shaped gourd will impress itself 
more strongly upon crosses than any of the edible 
squashes and pumpkins with which it will effect a 
cross, whether it is used as male or female parent. 
Even the imposing and ubiquitous great field 
pumpkin, which every New Englander associates 
with pies, is overpowered by the little gourd. 
Seeds from a large and sleek pumpkin which had 
been fertilized by gourd pollen, produced gourds 
and small hard-shelled globular fruits which were 
entirely inedible. A more interesting experiment 
was made between the handsome green-striped Ber- 
gen fall squash and the little pear gourd. Several 
flowers of the gourd were pollinated by the Bergen 
in 1889. The fruits raised from these seeds in 
1890 were remarkably gourd-like. Some of these 
crosses were pollinated again in 1890 by the Ber- 
gen, and the seeds were sown in 1891. Here, 
then, were crosses into which the gourd had gone 
once and the Bergen twice, and both the parents 
are to all appearances equally fixed, the difference 
in strength, if any, attaching rather to the Bergen. 



POLLINATION IS UNCERTAIN. 83 

Now, the crop of 1891 still carried pronounced 
characters of the gourd. Even in the fruits which 
most resembled the Bergen, the shells were almost 
flinty hard, and the flesh, even when thick and 
tender, was bitter. Some of the fruits looked so 
much like the Bergen that I was led to think that 
the gourd had largely disappeared. The very hard 
but thin paper-like shell which the gourd had laid 
over the thick yellow flesh of the Bergen, I 
thought might serve a useful purpose, and make 
the squash a better keeper. And I found that it 
was a great protection, for the squash could stand 
any amount of rough handling, and was even not 
injured by ten degrees of frost. All this was an 
acquisition, and, as the squash was handsome and 
exceedingly productive, nothing more seemed to 
be desired. But it still remained to have a squash 
for dinner. The cook complained of the hard 
shell, but, once inside, the flesh was thick and 
attractive, and it cooked nicely. But the flavor ! 
Dregs of quinine, gall, and boneset! The gourd 
was still there ! 

VI. Uncertainties of Pollination. 

We have now seen that uncertainty follows 
hybridization, and, in closing, I will say that 
uncertainty also attaches to the mere act of 
pollination. Between some species which are 



84 PHILOSOPHY OF CROSSING PLANTS. 

closely allied and which have large and strong 
flowers, four-fifths of the attempts towards cross- 
pollination may be successful ; but such a large 
proportion of successes is not common, and it 
may be infrequent even in pollinations between 
plants of the same species or variety. Some of 
the failure is due in many cases to unskilful opera- 
tion, but even the most expert operators fail as 
often as they succeed in promiscuous pollinating. 
There is good reason to believe, as Darwin has 
shown, that the failure may be due to some selec- 
tive power of individual plants, by which they re- 
fuse pollen which is, in many instances, acceptable 
to other plants even of the same variety or stock. 
The lesson to be drawn from these facts is that 
operations should be as many as possible, and that 
discouragement should not come from failure. 
In order to illustrate the varying fortunes of the 
pollinator, I will transcribe some notes from my 
field-book. 

Two hundred and thirty-four pollinations of 
gourds, pumpkins, and squashes, mostly between 
varieties of one species (Cucurbita Pepo), and in- 
cluding some individual pollinations, gave one 
hundred and seventeen failures and one hundred 
and seventeen successes. These crosses were made 
in varying weather, from July 28 to August 30. 
In some periods nearly all the operations would 
succeed, and at other times most of them would 



RECORDS OF POLLINATIONS. $5 

fail. I have always regarded these experiments as 
among my most successful ones, and yet but half 
of the pollinations " took." But one must not 
understand that I actually secured seeds from even 
all these one hundred and seventeen fruits, for 
some of them turned out to be seedless, and some 
were destroyed by insects before they were ripe, or 
they were lost by accidental means. A few more 
than half of the successful pollinations — if by suc- 
cess we mean the formation and growth of fruit — 
really secured us seeds, or about one-fourth of the 
whole number of efforts. 

Twenty pollinations were made between potato 
flowers, and they all failed ; also, seven pollinations 
of red peppers, four of husk-tomato, two of Nico- 
tiana affinis upon petunia and two of the reciprocal 
cross, twelve of radish, one of Mirabilis Jalapa upon 
M. longiflora and two of the reciprocal cross, three 
Convolvulus major upon C. minor and one of the 
reciprocal, one muskmelon by squash, two musk- 
melons by watermelon, and one muskmelon by 
cucumber. 

This is but one record. Let me give another : — 
Cucumber, ninety-five efforts : fifty-two suc- 
cesses, forty-three failures. Tomato, forty-three 
efforts : nineteen successes, twenty-four failures. 
Egg-plant, seven efforts : one success, six failures. 
Pepper, fifteen efforts : one success, fourteen fail- 
ures. Husk -tomato, forty-five efforts : forty-five 



86 PHILOSOPHY OF CROSSING PLANTS. 

failures. Pepino, twelve efforts : twelve failures. 
Petunia by Nicotiana affinis, eleven efforts : eleven 
failures. Nicotiana affinis by petunia, six efforts : 
six failures. General Grant tobacco by Nicotiana 
affinis, eleven efforts : eight successes, three fail- 
ures. Nicotiana affinis by General Grant tobacco, 
fifteen efforts : fifteen failures. General Grant 
tobacco by General Grant tobacco, one effort : one 
success. Nicotiana affinis by Nicotiana affinis, three 
efforts : two successes, one failure. Tuberous be- 
gonia, five efforts : five successes. 

Total, three hundred and twelve efforts : eighty- 
nine successes, two hundred and twenty-three 
failures. 

Conclusion. 

And now, the sum of it all is this : encourage in 
every way crosses within the limits of the variety 
and in connection with change of stock, expecting 
increase in vigor and productiveness ; hybridize 
if you wish to experiment, but do it carefully, 
systematically, thoroughly, and do not expect too 
much. Extend Darwin's famous proposition to 
read: Nature abhors both perpetual self-fertiliza- 
tion and hybridization. 



LECTURE III. 

HOW DOMESTIC VARIETIES ORIGINATE. 

" The key is man's power of accumulative 
selection : nature gives successive variations ; 
man acids them up in certain directions useful 
to him." This, in Darwin's phrase, is the essence 
of the cultivator's skill in ameliorating the vege- 
table kingdom. So far as man is concerned, the 
origin of the initial variation is largely chance, 
but this start or variation once given, he has the 
power, in most cases, to perpetuate it and to 
modify its characters. There are, then, two very 
different factors or problems in the origination of 
garden varieties, — the production of the first de- 
parture or variation, and the subsequent breeding 
of it. Persons who give little thought to the sub- 
ject, look upon variation as the end of their endeav- 
ors, thinking that a form comes into being with all 
its characters well marked and fixed. In reality, 
however, variation is but the beginning ; selection 
is the end. 

I. Indeterminate Varieties. 

There are two general classes of garden varie- 
ties as respects the method of their origin, — 

87 



88 HOW DOMESTIC VARIETIES ORIGINATE. 

those which come into existence somewhat sud- 
denly and which require little else of the hus- 
bandman than the multiplication of them, and 
those which are the result of a slow evolution or 
direct breeding. The former are indeterminate 
or uncertain, and the latter are determinate or 
definite. The greater part of those in the first 
class are plants which are multiplied or divided 
by bud-propagation. They comprise nearly all 
our fruits, the woody ornamental plants, and such 
herbaceous genera as begonia, canna, gladiolus, 
lily, dahlia, carnation, chrysanthemum, and the 
like, — in fact, all those multiplied by grafting, 
cuttings, bulbs, or other asexual parts. The 
original plant may be either a seedling or a bud- 
sport. The gardener, avIio is always on the look- 
out for novelties, discovers its good qualities and 
propagates it. 

Varieties which are habitually multiplied by 
buds, as in those plants which I have mentioned 
in the last paragraph, vary widely when grown 
from seeds, so that every seedling may be 
markedly distinct. As soon, however, as varie- 
ties are widely and exclusively propagated by 
seeds, they develop a capability of carrying the 
greater part of the individual differences down 
to the offspring. That is, seedlings from bud- 
multiplied plants do not " come true," as a rule, 
whilst those from seed - propagated plants do 



INDETERMINATE VARIETIES. 89 

"come true." The reason of this difference will 
become apparent upon a moment's reflection. In 
the seed-propagated plants, like the kitchen-gar- 
den vegetables and the annual flowers, we select 
the seeds and thereby eliminate all those varia- 
tions which would have arisen had the discarded 
seeds been sown. In other words, we are con- 
stantly fixing the tendency to " come true," for 
this feature of plants is as much a variation as 
form or color or any other attribute is. Suppose, 
for instance, that a certain variation were to re- 
ceive two opposite treatments, the seeds from one- 
half of the progeny being carefully selected year 
by year, and all those from untypical plants dis- 
carded, whilst in the other half all the seeds from 
all the plants, whether good or bad, are saved 
and sown, In the one case, it will be seen, we 
are fixing the tendency to " come true," for this 
is all that constitutes a horticultural variety, — 
a brood which is very much like all its parents. 
In the other case, we are constantly eliminating 
the tendency to " come true " by allowing every 
modifying agency full sway. So the very act of 
taking seeds only from plants which have " come 
true," tends to still more strongly fix the heredi- 
tary force within narrow limits. Working against 
this restrictive force, however, are all the agencies 
of environment, so that, fortunately, now and 
then a seed gives a " rogue," or a plant widely 



90 HOW DOMESTIC VARIETIES ORIGINATE. 

unlike its parent, and this may be the start for a 
new variety. 

With bud-multiplied varieties, however, the 
case is very different. Here every seed may be 
sown, as in the illustrative case above, because 
the seedlings are not wanted for themselves, but 
simply as stocks upon which to bud or graft the 
desired varieties. So there is no seed selection in 
the ordinary propagation of apples, pears, peaches, 
and the other orchard fruits. The seeds are taken 
indiscriminately from pomace or the refuse of can- 
ning and evaporating factories. But every annual 
garden vegetable is always grown from seeds more 
or less carefully saved from plants which possess 
some desired attribute. There is no reason why 
the tree fruits should not reproduce themselves 
from seeds just as closely as the annual herbs do, if 
they were to be as carefully propagated by selected 
seeds through a long course of generations. There 
is excellent proof of this in the well-marked races 
or families of Russian apples. In that country, 
grafting has been little employed, and conse- 
quently it has been necessary to select seeds 
only from acceptable trees in order that the off- 
spring might be more acceptable. So the Russian 
apples have come to run in groups or families, each 
family bearing the mark of some strong ancestor. 
Most of the seedlings of the Duchess of Olden- 
burg are recognizable because of their likeness to 



PLANT-BREEDING. 91 

the parent. We may thus trace an incipient ten- 
dency in our own fruits towards racial characters. 
The Fameuse type of apples, for example, tends to 
perpetuate itself ; and a similar tendency is very 
well marked in the Damson and Green Gage 
plums, the Orange quince, Concord grape, and 
Hill's Chili and Crawford peaches. But inas- 
much as bud-multiplication is so essential in 
nursery practice, we can hardly hope for the 
time when our trees and shrubs, or even our per- 
ennial herbs, will " come true " with much cer- 
tainty. In them, therefore, we get new varieties 
by simply sowing the seeds ; but in seed-propa- 
gated varieties we must depend either upon chance 
variations or else we must resort to definite plant- 
breeding. 

II. Plant -breeding. 

The breeding of domestic animals is attended, 
for the most part, with such definite and often 
precise results that there has come to be a gen- 
eral desire to extend the same principles to 
plants. It is not unusual to hear well-informed 
people say that it is possible to breed plants with 
as much certainty and exactness as it is to breed 
animals. The fact is, however, that such exact- 
ness will never be possible, because plants are 
very unlike animals in organization, and because, 



92 HOW DOMESTIC VARIETIES ORIGINATE. 

also, the objects sought in the two cases are char- 
acteristically unlike. Plants, as we have seen, are 
made up of a colony of potential individuals, and 
to breed between two plants by crossing means 
that we must choose the sex-parents from amongst 
as many individuals as there are flowers or branches 
on the two plants, whilst in animals we choose two 
definite personal parents. And these personal 
parents are either male or female, and the union 
is essential to the production of offspring, whilst 
in plants each parent — that is, each flower — is 
generally both male and female, and the union of 
two is not essential to the production of offspring, 
for the plant is capable of multiplying itself by 
buds. The element of chance, therefore, is one 
hundred, or more, to one in crossing plants as 
compared with crossing animals. Then, again, 
the plant-parents are modified profoundly by every 
environmental condition of soil and temperature 
and sunshine, or other external condition, since 
they possess no bodily temperature, no choice of 
conditions, and no volition to enable them to 
overcome the circumstances in which they are 
placed. Animals, on the contrary, have all these 
elements of personality, and the breeder is also 
able to control the conditions of their lives to a 
nicety. In view of all these facts, it is not strange 
that animals can be bred by crossing with more 
confidence than plants can. But there is another 



ANIMALS AND PLANTS. 93 

and even more important difference between the 
breeding of animals and the breeding of plants. 
In animals, onr sole object is to secure simply one 
animal or one brood of offspring. In plants, our 
object is, in general, to secure a race or genera- 
tions of offspring, which may be disseminated 
freely over the earth. In the bovine race, for 
example, our object in breeding is to produce one 
cow with given characters ; in turnips, our object 
is to produce a new variety, the seed of which 
will reproduce the variety, whether sown in Penn- 
sylvania or Ceylon. It is apparent, therefore, that 
any comparisons drawn between the breeding of 
animals and plants are likely to be fallacious. 

Is there, then, any such thing as plant-breeding, 
any possibility that the operator can proceed with 
some confidence that he may obtain the ideal 
which he has in mind ? Yes, to a certain extent. 

It is apparent that the very first effort on the 
part of the plant-breeder must be to secure indi- 
vidual differences ; for so long as the plants which 
he handles are very closely alike, so long there 
will be little hope of obtaining new varieties. He 
must, therefore, cause his plants to vary. In 
plants which are comparatively unvariable, it is 
frequently impossible to produce variations in the 
desired direction at once, but it is more important 
to "break " the type, — that is, to make it depart 
markedly from its normal behavior in any or 



94 HOW DOMESTIC VARIETIES ORIGINATE. 

many directions (page 19). If the type once 
begins to vary, to break up into different forms, 
the operator may be sure that it will soon become 
plastic enough to allow of modification in the 
manner which he desires. But whilst it is im- 
portant or even necessary to break a well-marked 
type into many forms, it would no doubt be un- 
wise to encourage this tendency after it once 
appears, lest the plant acquire a too strong habit 
of scattering. This initial variation is induced 
by changing the conditions in which the plant has 
habitually grown, as a change of seed, change of 
soil, tillage, varying the food supply, crossing and 
the like. 

As a matter of fact, however, nearly all plants 
which have been long cultivated are already suf- 
ficiently variable to afford a starting-point for 
breeding. The operator should have a vivid 
mental picture of the variety which he designs to 
obtain ; then he should select that plant in his 
plantation which is the nearest his ideal, and sow 
the seeds of it. From the seedlings he should 
again select the individuals which most nearly 
approach his type, and so on, generation after 
generation, until the desired object is attained. 
It is important, if he is to make rapid progress, 
that he keep the same ideal in mind year by year, 
otherwise there will be vacillation and the prog- 
ress of one year may be undone by a counter 



ANTAGONISTIC FEATURES. 95 

movement the following year. In this way, it 
will be found that almost any character of a plant 
may be either intensified or lessened. This is 
man's nearest approach to the Creator in his 
dominion over the physical forms of life, and it 
is great and potent in proportion as it sets for 
itself correct ideals in the beginning and adheres 
to them until the end. 

When beginning this selection or breeding for 
an ideal, it is important that impossible or contra- 
dictory results should be avoided. Some of the 
cautions and suggestions which need to be con- 
sidered are these : — 

1. Avoid striving after features ivhich are antag- 
onistic or foreign to the species or genus with which 
you are working. Every group of plants has be- 
come endowed with certain characters or lines 
of development, and the cultivator will secure 
quicker and surer results if he works along the 
same lines, rather than to attempt to thwart them. 
Nature gives the hint : let men follow it out, 
rather than to endeavor to create new types of 
characters. Let us take some of the solanaceous 
plants as examples. There are certain types of 
the genus solanum which have a natural habit of 
tuber-bearing, as the potato. Such species should 
be bred for tubers and not for fruits. There are 
other solanums, however, like the egg-plants and 
the pepinoes, which naturally vary or develop in 



96 HOW DOMESTIC VARIETIES ORIGINATE. 



the direction of fruit-bearing, and these should be 
bred for fruits and not for tubers ; and the same 
should be true in the related genera of tomatoes, 
red peppers, and physalis. Those ambitious per- 
sons who are always looking for a tuber-bearing 
tomato, therefore, might better concentrate their 
energies on the potato, for the tomato is not devel- 
oping in that direction ; and even if the tomato 
could be made to produce tubers, it would thereby 
lessen its fruit production, for plants cannot main- 
tain two diverse and profitable crops at the same 
time. It is more reasonable, and certainly more 
practicable, to grow potatoes on potato plants and 
tomatoes on tomato plants. 

2. The quickest and most marked results are to 
be expected in those groups or species which are nor- 
mally the most variable. There are a greater num- 
ber of variations or starting-points in such species ; 
but it also follows that the forms are less stable 
the more the species is variable. Yet the varia- 
tions, being very plastic, }deld themselves readily 
to the wishes of the operator. Carriere puts the 
thought in this form : " The stability of forms, in 
any group of plants, is, in general, in inverse ratio 
to the number of the species which it contains, 
and also to the degree of its domestication." 

The most variable types are the most dominant 
ones over the earth ; that is, they occur in greater 
numbers and under more diverse conditions than 



VARIABLE TYPES. 97 

the comparatively invariable types do. The com- 
posite, or sunflower-like plants, comprise a ninth 
or tenth of the total species of flowering plants, 
and the larger part of the subordinate types or 
genera contain many forms or species. Aster, 
goldenrod, the hawkweeds, thistles, and other 
groups, are representative of the cosmopolitan or 
variable types of composites. Whenever, for any 
reason, any type begins to decline in variability, 
it also begins to perish ; it is then tending towards 
extinction. Monotypic genera — those which con- 
tain but a single species — are generally of local 
or disconnected distribution, and are, for the most 
part, vanishing remnants of a once dominant or 
important type. As a rule, most of our widely 
variable and staple cultivated species are mem- 
bers of large, or at least polytypic genera. Such, 
for example, are the apples and pears, peaches 
and plums, oranges and lemons, roses, bananas, 
chrysanthemums, pinks, cucurbits, beans, potato, 
grapes, barley, rice, cotton. A marked exception 
to this statement is maize, which is immensely 
variable and is generally held to have come from 
a single species ; but the genesis of maize is un- 
known, and it is possible, though scarcely proba- 
ble, that more than one species is concerned in it. 
Wheat is also a partial exception, although the 
original specific type is not understood ; and the 
latest monographers admit three or four other spe- 



98 HOW DOMESTIC VARIETIES ORIGINATE. 

cies to the genus, aside from wheat. There are 
other exceptions, but they are mostly unimportant, 
and, in the main, it may be said that the domi- 
nant domestic types of plants represent markedly 
polytypic genera. 

3. Breed for one thing at a time. The person 
who strives at the same time for increase or modi- 
fication in prolificacy and flavor will be likely to 
fail in both. He should work for one object 
alone, simply giving sufficient attention to sub- 
sidiary objects to keep them up to normal stand- 
ard. This is really equivalent to saying that 
there can be no such thing as the perfect all- 
around variety which so many people covet. Va- 
rieties must be adapted to specific uses, — one for 
shipping, one for canning, one for dessert, one for 
keeping qualities, and the like. The more good 
varieties there are of any species, the more widely 
and successfully that species can be cultivated. 

4. Do not desire contradictory attributes in any 
variety. A variety, for example, which bears the 
maximum number of fruits or flowers cannot be 
expected to greatly increase the size of those 
organs without loss in numbers. This is well 
shown in the tomato. The original tomato pro- 
duced from six to ten fruits in a cluster, but as 
the fruits increased in size the numbers in each 
cluster fell to two or three. That is, increase in 
size proceeded somewhat at the expense of numer- 



SELECT FOR THE ENTIRE PLANT. 99 

ical productivity ; yet the total weight of fruit 
per plant has greatly increased. The same is 
true of apples and pears ; for whilst these trees 
bear flowers in clusters, they generally bear their 
fruits singly. Originally, every flower normally 
set fruit. The reason why blackberries, currants, 
and grapes do not increase more markedly in size, 
is probably because the size of cluster has been 
given greater attention than the size of berry- 
Plants which now bear a full crop of tubers 
cannot be expected to increase greatly in fruit- 
bearing, as I have already explained under 
Rule 1. This fact is illustrated in the potato, 
in which, as tuber production has increased, seed 
production has decreased, so that potato growers 
now complain that potatoes do not produce bolls 
as freely as they did years ago. 

5. Whe7i selecting seeds, remember that the char- 
acter of the whole plant is more important than the 
character of any one branch or part of the plant ; 
and the more uniform the plant in all its parts, the 
greater is the likelihood that it will transmit its 
characters. If one is striving for larger flowers, 
for instance, he will secure better results if he 
choose seeds from plants which bear large flowers 
throughout, than he will if he choose them from 
some one large-flowering branch on a plant which 
bears indifferent flowers on the remaining branches, 
even though this given branch produce much larger 

LOFC. 



100 HOW DOMESTIC VARIETIES ORIGINATE. 

flowers than those borne on the large -flowered 
plant. Small potatoes from productive hills give 
a better product than large potatoes from unpro- 
ductive hills. The practice of selecting large 
ears from a bin of corn, or large melons from the 
grocer's wagon, is much less efficient in produc- 
ing large products the following season than the 
practice of going into the fields and selecting the 
most uniformly large-fruited parents would be. 
A very poor plant may occasionally produce one 
or two very superior fruits, but the seeds are 
more likely to perpetuate the characters of the 
plant than of the fruits. 

The following experiences detailed by Henri L. 
de Vilmorin illustrate my proposition admirably: 
" I tried an experiment with seeds of Chrysanthe- 
mum carinatum gathered on double, single, and 
semi-double heads, all growing on one plant, 
and found no difference whatever in the propor- 
tion of single and double-flowered plants. In 
striped verbenas, an unequal distribution of the 
color is often noticed ; some heads are pure white, 
some of a self color, and most are marked with 
colored stripes on white ground. I had seeds 
taken severally from all and tested alongside 
one another. The result was the same. All the 
seeds from one plant, whatever the color of the 
flower that bore them, gave the same proportion 
of plain and variegated flowers." 



TJNIFORMNESS IN THE PARTS. 101 

The second part of my proposition is equally as 
important as the first, — the fact that a plant 
which is uniform in all its branches or parts is 
more likely to transmit its general features than 
one which varies within itself. It is well known 
that bean plants often produce beans with various 
styles of markings on the same plant or even in 
the same pod, yet these variations rarely ever 
perpetuate themselves. The same remark may 
be applied to variations in peas. These illustra- 
tions only add emphasis to the fact that intending 
plant-breeders should give greater heed than they 
usually do to the entire plant, rather than confine 
their attention to the particular part or organ 
which they desire to improve. 

At first thought, it may look as if these facts 
are directly opposed to the proposition which I 
emphasized in my first lecture, that every branch 
of a plant is a potential autonomy, but it is really 
a confirmation of it. The variation itself shows 
that the branch is measurably independent, but it 
is not until the conditions or causes of the vari- 
ation are powerful enough to affect the entire 
plant that they are sufficiently impressed upon 
the organization of the plant to make their effects 
hereditary. 

There is an apparent exception to the law that 
the character of the entire plant is more impor- 
tant than any one organ or part of it, in the case 



102 HOW DOMESTIC VARIETIES ORIGINATE. 

of the seeds themselves. That is, better results 
usually follow the sowing of large and heavy 
seeds than of small or unselected seeds from the 
same plant. This, however, does not affect the 
main proposition, for the seed is in a measure 
independent of the plant-body, and is not so 
directly influenced by environment as the other 
organs are. And, again, the seed receives a part 
of its elements from a second or male parent. 
The good results which follow the use of large 
seeds are, chiefly, greater uniformity of crop, 
increased vigor, often a gain in earliness and 
sometimes in bulk, and generally a greater ca- 
pacity for the production of seeds. These results 
are probably associated less with any innate he- 
reclitable tendencies than with the mere vegeta- 
tive strength and uniformness of the large seeds. 
The large seeds usually germinate more quickly 
than the small ones, provided both are equally 
mature, and they push the plantlet on more 
vigorously. This initial gain, coming at the 
most critical time in the life of the new indi- 
vidual, is no doubt responsible for very much of 
the result which follows. The uniformity of crop 
is the most important advantage which comes of 
the use of large seeds, and this is obviously the 
result of the elimination of all seeds of varying 
degrees of maturity, of incomplete growth and 
formation, and of low vitality. 



PROGENY OF IMMATURE SEEDS 103 

Another important consideration touching the 
selection of seeds is the fact that very immature 
seeds give a feeble but precocious progeny. This 
has long been observed by gardeners, but Sturte- 
vant, Arthur, and Goff have recently made a 
critical examination of the subject. " It is not 
the slightly unripe seeds that give a noticeable 
increase in earliness," according to Arthur, " but 
very unripe seeds, gathered from fruit [tomatoes] 
scarcely of full size and still very green. Such 
seeds do not weigh more than two-thirds as much 
as those fully ripe. They germinate readily, but 
the plantlets lack constitutional vigor and are 
more easily affected by retarding or harmful 
influences. If they can be brought through the 
early period of growth and become well estab- 
lished, and the foliage or fruit is not attacked by 
rots or blights, the grower will usually be re- 
warded by an earlier and more abundant crop of 
slightly smaller and less firm fruit. These char- 
acters will be more strongly emphasized in sub- 
sequent years by continuous seed propagation. " 
Goff remarks that the increase in earliness in 
tomatoes, following the use of markedly immature 
seeds, "is accompanied by a marked decrease in 
the vigor of the plant, and in the size, firmness, 
and keeping quality of the fruit." These results 
are probably closely associated with the chemical 
constitution and content of the immature seeds. 



104 HOW DOMESTIC VARIETIES ORIGINATE. 

The organic compounds have probably not yet 
reached a state of stability, and they therefore 
respond quickly to external stimuli when placed 
in conditions suitable to germination ; and there 
is little food for the nourishment of the plantlet. 
The consequent weakness of the plantlet results 
in a loss of vegetative vigor, which is earliness 
(see Rule 11). 

Still another feature connected with the choice 
of seeds is the fact that in some plants, as in some 
Ipomceas, for example, the color of the seed is 
more or less intimately associated with the color 
of the flower which produced them and also with 
the color of the flowers which they will produce. 

6. Plants which have any desired characteristics 
in common may differ widely in their ability to 
transmit these characters. It is generally impos- 
sible for the cultivator to determine, from the 
appearance of any given number of similar plants, 
which of them will give progeny the most unvari- 
able and the most like its parent ; but it may be 
said that those individuals which grow in the most 
usual or normal environments are most likely to 
perpetuate themselves. A very unusual condi- 
tion, as of soil, moisture, or exposure, is not easily 
imitated when providing for the succeeding gen- 
eration, and a return to normal conditions of envi- 
ronment may be expected to be followed by a more 
or less complete return to normal attributes on the 



SELECT SEVERAL STARTING-POINTS. 105 

part of the plant. If the same variation, there- 
fore, were to occur in plants growing under widely 
different conditions, the operator who wishes to 
preserve the new form should take particular care 
to select his seeds from those individuals which 
seem to have been least influenced by the imme- 
diate conditions in which they have grown. 

Again, if the same variation appears both in 
uncrossed and crossed plants, the best results 
should be expected in selecting seeds from the 
former. We have already seen, in the second 
lecture, how it is that crosses are unstable, and 
how the instability is apt to be the greater the 
more violent the cross. " Cross-breeding greatly 
increases the chance of wide variation," writes 
Henri L. de Vilmorin, " but it makes the task of 
fixation more difficult." 

It is very important, therefore, when selecting 
seeds from plants which seem to give promise of 
a new variety, to sow the seeds of each plant 
separately, and then make the subsequent selec- 
tions from" the most stable generation; and it is 
equally important that the operator should not 
trust to a single plant as a starting-point, when- 
ever he has several promising plants from which 
to choose. 

7. The less marked the departure from the 
genius of the normal type, the greater, in general, 
is the likelihood that it will be perpetuated. That 



106 HOW DOMESTIC VARIETIES ORIGINATE. 

is, widely aberrant forms are generally unstable. 
This is admirably illustrated in crosses. The 
seed-progeny of crosses between closely related 
varieties, or between different plants of the same 
variety, is more uniform and generally more easy 
of improvement by selection than the progeny of 
hybrids. In uncrossed plants, the general ten- 
dency is to resemble their parents, and the greater 
the number of like ancestors, the greater is the ten- 
dency to "come true." There is thought to be a 
tendency, though necessarily a weak one, to return 
to some particular ancestor, or to "date back." 
This is known as atavism. The so-called atavistic 
forms are likely to be unstable, to break up into nu- 
merous forms, or to return more or less completely 
to the type of the main line of the ancestry. The 
following statements touching some of the rela- 
tions of atavism to the amelioration of plants, are 
the results of an excellent study of heredity in 
lupines by Louis Leveque de Vilmorin : — 

"1. The tendency to resemble its parents is 
generally the strongest tendency in any plant; 

"2. But it is notably impaired as it comes 
into conflict with the tendency to resemble the 
general line of its ancestry. 

" 3. This latter tendency, or atavism, is con- 
stant, though not strong, and scarcely becomes 
impaired by the intervention of a series of gen- 
erations in which no reversion has taken place. 



CROSSING NOT AN END. 107 

"4. The tendency to resemble a near pro- 
genitor (only two or three generations removed), 
on the other hand, is very soon obliterated if the 
given progenitor is different from the bulk of 
its ancestors." 

8. The crossing of plants should be looked upon 
as a means or starting-point, not as an end. We 
cross two flowers and sow the seeds. The result- 
ing seedlings may be unlike either parent. Here, 
then, is variation. The operator should select 
that plant which most nearly satisfies his ideal, 
and then, by selection from its progeny and the 
progeny of succeeding generations, gradually ob- 
tain the plant which he desires. It is only in 
plants which are propagated by asexual parts — as 
grafts, cuttings, layers, bulbs, and the like — that 
hybrids or crosses are commonly immediately val- 
uable; for in these plants we really cut up and 
multiply the one individual plant which pleases us 
in the first batch of seedlings, rather than to take 
the offspring or seedlings of it. Thus, if any 
particular plant in a lot of seedlings of crosses 
of cannas, or plums, or hops, or strawberries, or 
potatoes, is valuable, Ave multiply that one in- 
dividual. There is no occasion for fixing the 
variety. But any satisfactory plant in a lot of seed- 
lings of crosses of pumpkins, or wheat, or beans, 
must be made the parent of a new variety by sow- 
ing the seeds of it and then by selecting for seed- 



108 HOW DOMESTIC VARIETIES ORIGINATE. 

parents, year by year, those plants which are best. 
" The unsettled forms arising from crosses," Focke 
writes, " are the plastic material out of which 
gardeners form their varieties." 

But even in the fruits, and other bud-propa- 
gated plants, crossing may often be used to as 
good advantage for the purpose of originating 
variation as it can in peas or buckwheat. It only 
requires a longer time to fix and select variations 
because the plants mature so sloAvly. Ordinarily, 
if the operator does not find satisfactory plants 
amongst the seedlings of any cross of fruit trees, 
he roots up the whole batch as profitless. But if 
he were to allow the best plants to stand and 
were to sow seeds from them, the second gen- 
eration might produce something more to his 
liking. But it is generally quicker to make 
another cross and to try the experiment over 
again, than to wait for unpromising seedlings to 
bear. This repeated repetition of the experiment, 
however, — continual crossing and sowing and 
uprooting, — is gambling. Throwing dice to see 
what will turn up is a comparable proceeding. 
The sowing of uncrossed seed is little better. 
Peter M. Gideon sowed over a bushel of apple 
seed, and one seed produced the Wealthy apple. 1 

1 The facts in the origination of the Wealthy apple, as re- 
lated to ine by Mr. Gideon, are these : he first planted a bushel 
of apple seeds, and then each year, for nine years, he planted 



GUIDES TO CROSSING. 109 

D. B. Wier raised a million seedlings of soft 
maple, and one plant of the lot had finely divided 
leaves, and is now Wier's Cntleaved maple. Teas' 
Weeping mulberry, which is now so deservedly 
popular, was, as Mr. Teas tells me, " merely an 
accidental seedling." So this explains why the 
production of new varieties of fruits is always 
chance, whilst a skilled man can sit in his study 
in the winter time and picture to himself a new 
bean or muskmelon, and then go out in the next 
three or four summers and produce it. 

9. If it is desired to employ crossing as a direct 
means of producing new varieties, each parent to the 
proposed cross should he selected in agreement with 
the rules already specified, and also because it pos- 
sesses in an emphatic degree one or more of the 
qualities which it is desired to combine ; and the 
more uniformly and persistently the parent pre- 
sents a given character, the greater is the chance that 
it will transmit that character. It has already 
been said that crossing for the instant production 
of new varieties is most certain to give valuable 

enough seed to give a thousand trees. At the end of ten years, 
all the seedlings had perished (this was in Minnesota) except 
one hardy seedling crab. Then a small lot of seeds of apples 
and crab apples was obtained in Maine, and from these the 
Wealthy came. There were only about fifty seeds in the 
batch of crab seed which gave the Wealthy ; but before this 
variety was obtained, much over a bushel of seed had been 
sown. 



110 HOW DOMESTIC VARIETIES ORIGINATE. 

results in those species which are propagated by 
buds, because the initial individual differences 
are not dissipated by seed-reproduction. This 
is especially true of hybridization, or crossing 
between distinct species ; for in such violent cross- 
ing as this the offspring is particularly likely to 
be unstable when propagated by seeds. The re- 
sults of hybridization appear to be most certain 
in those plants which are grown under glass, and 
in which, therefore, the selection of the seed- 
parents is most carefully made, and where the 
conditions of existence are most uniform. The 
most remarkable results in hybridization which 
have yet been attained are with the choicer glass- 
house plants, such as orchids, begonias, anthu- 
riums, and the like. (Lecture II.) 

The more violent the cross, the less is the likeli- 
hood that desirable offspring will follow. Species 
which refuse to give satisfactory results when 
hybridized directly or between the pure stocks, 
may give good varieties when the " blood " has 
become somewhat attenuated through previous 
crossings. The best results in hybridizing our 
native grape with the European grape, for ex- 
ample, have come from the use of one parent 
which is already a hybrid. Two notable examples 
are the Brighton and Diamond grapes, raised by 
Jacob Moore. The Brighton is a cross of Con- 
cord (pure native) by Diana-Hamburg (hybrid of 



IMPORTANT HYBRIDS OF FRUITS. Ill 

impure native and European). Diamond is a 
cross of Concord by Iona, the latter parent un- 
doubtedly of impure origin, containing a trace of 
the European vine. T. V. Munson's Brilliant is 
a secondary hybrid, its parents, Lindley and Dela- 
ware, both containing hybrid blood. Others of 
his varieties have similar histories. Even when 
the cross is much attenuated — or three or four 
or even more times removed from a pure hybrid 
origin by means of subsequent crossings — it may 
still produce marked effects in a cross without 
introducing such contradictory characters as to 
jeopardize the value of the offspring. 

Amongst American fruit plants there are com- 
paratively few valuable hybrids. The most con- 
spicuous ones are in the grapes, particularly the 
various Rogers varieties, such as Agawam, Lind- 
ley, Wilder, Barry, and others, which are hybrids 
of the European grape and a native species. 
Other hybrids are the Kieffer and allied pears 
(between the common pear and the Oriental 
pear), the Transcendent and a few other crabs 
(between the common apple and the Siberian 
crab), the Soulard and kindred crabs (between 
the common apple and the native Western crab), 
a few blackberries of the Wilson Early type 
(between the blackberry and the dewberry), the 
purple-cane raspberries (between the native red 
and black raspberries, and possibly sometimes 



112 HOW DOMESTIC VARIETIES ORIGINATE. 

combined with the European raspberry), the 
Utah Hybrid cherry (between the Western sand 
cherry and the sand plum), and probably a few 
of the native plums. There is undoubtedly a 
fertile field for further work in hybridizing our 
fruits, particularly those of native origin, and 
also many of the ornamental plants ; the danger 
is that persons are apt to expect too much from 
hybridization, and too little from the betterment 
of all the other conditions which so profoundly 
modify plants. Violent hybridizations generally 
give unsatisfactory and unreliable results; but 
subsequent crossings, when the "blood" of the 
original species to the contract is considerably 
attenuated, may be expected to correct or over- 
come the first incompatibility, as explained above. 
10. Establish the ideal of the desired variety 
firmly in the mind before any attempt is made at 
'plant-breeding . If one is to make any progress 
in securing new varieties, he must first be an 
expert judge of the capabilities and merits of 
the plants with which he is dealing, otherwise 
he may attempt the impossible or he may obtain 
a variety which has no merit. It is important, 
too, that the person bear in mind the fact that 
a variety which is simply as good as any other 
in cultivation is not worth introducing. It 
should be better in some particular than any 
other in existence. The operator must know the 



PRODUCE AN INITIAL VARIATION. 113 

points of his plant, as an expert stock-breeder 
knows the points of an animal, and he must 
possess the rare judgment to determine which 
characters are most likely to reappear in the 
offspring. Inasmuch as a person can be an ex- 
pert in only a few plants, it follows that he can- 
not expect satisfactory results in breeding any 
species which may chance to come before him. 
Persistent and uniform effort, continued over a 
series of years, is generally demanded for the 
production of really valuable varieties. Thus it 
often happens that one man excels all competitors 
in breeding a particular class of plants. The hor- 
ticulturist will recall, for instance, Lemoine in 
the breeding of gladiolus, Eckford in peas, Crozy 
in cannas, Bruant in pelargoniums, and others. 
There are now and then varieties which arise 
from no effort, but because of that very fact they 
reflect no credit upon the so-called originator, 
who is really only the lucky finder. So far as 
the originator is concerned, such varieties are 
merely chance. If, however, the operator — him- 
self an expert judge of the plant with which he 
deals — chooses his seeds with care and discrimi- 
nation, and then proposes, if need be, to follow up 
his work generation by generation by means of 
selection, the work becomes plant-breeding of the 
highest type. 

First of all, therefore, the operator must know 



114 HOW DOMESTIC VARIETIES ORIGINATE. 

what he can likely get, and what will likely be 
worth getting. Most persons, however, begin at 
the other end of the problem, — they get what 
they can, and then let the public judge if the 
effort has been worth the while. 

11. Having obtained a specific and correct ideal, 
the operator must next seek to make his plant vary 
in the desired direction. This may be done by 
crossing, or by modifying the conditions under 
which the plant grows, as indicated in Lectures 
I. and II. If there are any two plants which 
possess indications of the desired attributes, cross 
them: amongst the seedlings there may be some 
which may serve as starting-points for further 
effort. 

A change in the circumstances or environment 
of the plant may start the desired attribute. If 
the plant must be dwarfer, plant it on poorer or 
drier soil, transfer it towards the poles, plant it 
late in the season, or transplant it repeatedly (see 
pages 25 and 143). Dwarf peas become climb- 
ing peas on rich, moist soils. If the plant must 
have large fruits, allow it more food and room, 
and give attention to pruning and thinning. Cer- 
tain geographical regions develop certain charac- 
ters in plants, as we have seen (page 24); if, 
therefore, the desired feature does not appear 
spontaneously or as a result of any other treat- 
ment, transfer the plant for a time to that region 



PRODUCE AN INITIAL VARIATION. 115 

which is characterized by such attributes, if there 
is any such. 

The importance of growing the plant under 
conditions or environments in which the desired 
type of characters is most frequently found, is 
admirably emphasized in the evolution of varieties 
which are adapted to forcing under glass. Within 
a century, — and in many instances within a 
decade or two, — species which were practically 
unknown to glass-houses have produced varieties 
which are perfectly adapted to them. This has 
been accomplished by growing the most tractable 
existing varieties under glass, and then carefully 
and persistently selecting those which most com- 
pletely adapt themselves to their environment and 
to the ideals of the operator. One of the most 
remarkable examples of this kind is afforded by 
the carnation. In Europe it is chiefly a border 
or out-door plant, but within a generation it has 
produced hosts of excellent forcing varieties in 
America, where it is grown almost exclusively as 
a glass-house flower. So the carnation types of 
Europe and America are widely unlike, and the 
unlikeness becomes more emphatic year by year 
because of the rapid aberrant evolution of the 
American forms. 

Sowing the seeds of hardy annual plants in the 
fall often generates a tendency to produce thick- 
ened roots. The plant, finding itself unable to 



116 HOW DOMESTIC VARIETIES ORIGINATE. 

perfect seeds, stores its reserve in the root, and 
it therefore tends to become biennial. In this 
manner, with the aid of selection and the varia- 
tion of the soil, Carriere was able to produce good 
radishes from the wild slender-rooted charlock 
(Raphanus Raphanistrum). 

Lessened vigor, so long as the plant continues 
to be healthy, nearly always results in a compara- 
tive increase of fruits or reproductive organs. 
It is an old horticultural maxim that checking 
growth induces fruitfulness. It is largely in con- 
sequence of this fact that plants bear heaviest 
when they attain approximate maturity. Trees 
are often thrown into bearing by girdling, heavy 
pruning, the attacks of borers, and various acci- 
dental injuries. The gardener knows that if he 
keeps his plants in vigorous growth by con- 
stantly potting them on into larger pots, he will 
get little, or at least very late, bloom. The 
plant-breeder, therefore, may be able to induce 
the desired initial variation by attention to this 
principle. (See discussion of variation in rela- 
tion to food supply, page 16.) Arthur has re- 
cently put the principle into this formula : " A ' 
decrease in nutrition during the period of growth 
of an organism, favors the development of the re- 
productive parts at the expense of the vegetative 
parts." • 

A most important means of inducing variation 



SIMULTANEITY OF VARIATION. 117 

is the simple change of seed, the philosophical 
reasons for which are explained on pages 59 and 
28. A plant becomes closely fitted or accus- 
tomed to one set of conditions, and when it is 
placed in neAv conditions, it at once makes an 
effort to adapt itself to them. This adaptation 
is variation. No doubt the free interchange of 
seeds between seed-merchants and customers is 
one of the most fertile causes of the enormous 
increase in varieties in recent times. 

When once a novel variety appears, others of a 
similar kind are likely soon to follow in other 
places, and some persons have supposed that there 
is a synchronistic variation in plants, or a tendency 
for like variations to appear simultaneously in 
widely separated localities. There is perhaps 
some remote reason for this belief, because there 
is, as Darwin expresses it, an accumulative effect 
of domestication or cultivation, by virtue of which 
plants which long remain comparatively invariable 
may within a short time, when cultivation has 
been continued long enough, vary widely and in 
many directions; and it is to be expected that 
even when plants have long since responded to 
the wishes of the cultivator, an equal amount or 
accumulation of the force of domestication would 
tend to produce like effects in different places. 
But it is probable that by far the greater part of 
this synchronistic variation is simply an apparent 



118 HOW DOMESTIC VARIETIES ORIGINATE. 

one, for whenever any marked novelty appears the 
attention of all interested persons is directed to 
looking for similar variations amongst their own 
plants. 

12. The person who is wishing for new varieties 
should look critically to all perennial plants, and 
particularly to trees and shrubs, for bud-varieties 
or sports. It has already been said (pages 28, 6) 
that the branches of a tree may vary amongst 
themselves in the same way in which seedlings 
vary, and for the same reasons. As a rule, any 
marked sport is capable of being perpetuated by 
bud-propagation. The number of bud- varieties 
now in cultivation is really very large. Many of 
the cut-leaved and colored or variegated varieties 
of ornamental plants were originally found upon 
other trees as sports. The " mixing in the hill " 
of potatoes is bud-variation. Nectarines are 
derived from the peach, some of them as sports 
and some as seedlings. The moss-rose was prob- 
ably originally a sport from the Provence rose. 
Greening apple trees often bear russet apples, and 
russet trees sometimes bear greenings. So far as 
I know, there are no varieties of annual plants 
which have originated as sports. The probable 
reason for this is the fact that the duration of the 
plant is short and that its constitution is not pro- 
foundly modified in a single generation by the 
new circumstances in which it is placed every 



BUD- VARIETIES. 119 

year. The effects of the conditions in which it 
lives are recorded in the seeds, and the plant dies 
without allowing a second season of growth to 
express the impressions which were received in 
a former generation. The fact that every branch 
of an annual plant — as of perennials — is unlike 
every other branch, is evidence enough that the 
annual is not unlike the perennial in fundamental 
constitution ; and there is every reason to believe 
that if any given annual were to become a peren- 
nial, it would now and then develop differences 
sufficiently pronounced to make them worthy the 
name of sports, the same as hyacinths, bouvardias, 
trees, and all other perennial plants are apt to do. 
Bud- varieties may not only come true from buds 
— as grafts, cuttings and layers, — but they occa- 
sionally perpetuate themselves by seeds. Now, 
these seedlings are amenable to selection, just the 
same as any other seedlings are ; the bud- variety, 
therefore, may give the initial starting-point for 
plant-breeding. But, more than this, it is some- 
times possible to improve and fix the type by 
bud-selection as well as by seed-selection. Dar- 
win cites this interesting testimony : " Mr. Salter 
brings the principle of selection to bear on varie- 
gated plants propagated by buds, and has thus 
greatly improved and fixed several varieties. He 
informs me that at first a branch often produces 
variegated leaves on one side alone, and that the 



120 HOW DOMESTIC VARIETIES ORIGINATE. 

leaves are marked only with an irregular edging, 
or with a few lines of white and yellow. To im- 
prove and fix such varieties, he finds it necessary 
to encourage the buds at the bases of the most 
distinctly marked leaves and to propagate from 
them alone. By following, with perseverance, this 
plan during three or four successive seasons a dis- 
tinct and fixed variety can generally be secured." 
Ernest Walker, a careful gardener at New Albany, 
Indiana, is of the opinion that the abnormal char- 
acter of sports often intensifies itself if the sport 
is allowed to remain upon the parent plant for a 
considerable time. He has observed this particu- 
larly in coleus, where color sports are frequent. 
"In these," he says, "the sport begins with a 
branch, which may be taken off and propagated as 
a new variety. If left on the parent, other parts 
of the plant are apt to show similar variations. 
Indeed, I think it is not best to be in too great a 
hurry to remove a sporting branch, for its char- 
acter seems to tend to become more fixed if it 
remains on the plant." 

13. The starting-point once given, all permanent 
progress lies in continued selection. This, as I have 
already pointed out, is really the key to the whole 
matter. In the greater number of cases, the oper- 
ator cannot produce the initial variation which he 
desires, but, by looking carefully amongst many 
plants, he may find one which shows an indication 



SELECTION THE KEY-NOTE. 121 

of his ideal. This plant must be carefully saved, 
and all the seeds sown in a place where crossing 
with other types cannot take place. Of a hun- 
dred seedlings from this plant, mayhap one or 
two will still further emphasize the character 
which is sought. These, again, are saved and all 
the seeds are sown. So the operation goes on, 
patiently and persistently, and there is reward 
at the end. This is the one eternal and funda- 
mental principle which underlies the amelioration 
of plants under the touch of man ; and because 
we know, from experience, that it is so important, 
we are sure, as Darwin was, that selection in 
nature must be the most potent factor in the 
progress of the vegetable world. 

But suppose this suggestion of the new variety 
does not appear amongst the batch of plants 
which we raise? Then sow again: vary the con- 
ditions ; select the most widely variable types ; 
cross ; at length — if the ideal is true — the sug- 
gestion will come. " Cultivation, diversification 
of the conditions of existence, and repeated sow- 
ings " are the means which Verlot would employ 
to induce variations. But the skill and the char- 
acter of the final result lie not so much in the 
securing of the initial start, as in the subsequent 
selection. Nature affords starting-points in end- 
less number, but there are few men alert and skil- 
ful enough to take the hint and improve it. If I 



122 HOW DOMESTIC VARIETIES ORIGINATE. 

want a new tomato, I first endeavor to discover 
what I want. I decide that I must have one like 
the Acme in color, but more spherical, with a 
firmer flesh, and a little earlier. Then I shall 
raise an acre of Acme tomatoes, and closely allied 
varieties ; or if I cannot do that, I make arrange- 
ments to inspect my neighbor's fields. I scruti- 
nize every plant as the first fruits are ripening. 
Finally, I find one plant — not one fruit — which 
is something like the variety which I desire. 
Very well ! Wait two to five years, and you shall 
see my new variety ! 

Some of these initial variations possess no ten- 
dency to reproduce themselves. The seedlings of 
them may break up into a great diversity of 
forms, no form representing the parent closely. 
In such cases, it is generally useless to proceed 
further with this brood. Another start should be 
made with another plant. So it is always impor- 
tant, as we have already seen (Rule 6), to have as 
many starting-points as possible, to lessen the risk 
of failure. Whilst it requires nice judgment to se- 
lect those plants which possess the most important 
and the most transmissible combination of charac- 
ters, the greatest skill is nevertheless required to 
carry forward a correct system of selection. 

14. Even when the desired variety is obtained, it 
must be kept up to the standard by constant attention 
to selection. That is, there is no real stability in 



SELECTION TO MAINTAIN PURITY. 123 

the forms of plant life. So long as the conditions 
of existence vary, so long will plants make the 
effort to adapt themselves to the changes. No 
two seasons are alike, and no two fields, or even 
parts of fields, are alike ; and there are no two 
cultivators who give exactly the same and equal 
attention to tillage, fertilizing, and the other 
treatments of plants. All forms or varieties, 
therefore, tend to " run out " by variation or 
gradual evolution into other forms ; but because 
we keep the same name for all the succeeding 
generations, we fancy that we still have the same 
variety. In 1887 I found a single tomato plant 
in my garden in Michigan, which had several 
points of superiority over any other of the one 
hundred and seventy varieties which I was then 
growing. It came from a packet of German seed 
of an inferior variety. The tomato was very 
solid, an unusually long keeper, productive, and 
attractive in size and appearance. The variation 
was so promising that I named it in a sketch of 
tomatoes which I published that year, calling it 
the Ignotum (that is, unknown), to indicate that 
the origin of it was no merit of my own. I sent 
seeds to a few friends for testing. I sowed the 
seeds for about five hundred plants in 1888 in 
an isolated patch upon uniform soil. The larger 
part of the plants were more or less like the 
parent. A few reverted. A few of the best 



124 HOW DOMESTIC VARIETIES ORIGINATE. 

plants were selected, and the seed saved. I 
then moved to New York and took the seed with 
me. This was sown in uniform soil in an iso- 
lated position in 1889. This crop, probably as 
a result of the careful selection of the year before 
and of the change of locality, was remarkably 
uniform and handsome. Of the 4-42 plants which 
I grew that year, none reverted to the little 
Eiformige Dauer, the German variety from which 
it had come, but there was some variation in them 
due to different methods of treatment. I again 
saved the seeds, and I was now ready to intro- 
duce the variety. I therefore sold my seed, six 
pounds, to V. H. Hallock & Son, Queens, New 
York, who introduced it in 1800. The very next 
year, 1891, I obtained the Ignotum from fifteen 
dealers and grew the plants side by side. Of the 
fifteen lots, eight bore small and poor fruits which 
were not worth growing and Avhich could not be rec- 
ognized as Ignotum ! Grown from our own seed, 
it still held its characters well. Here, then, only 
a year after its introduction, half the seedsmen 
were selling a spurious stock. It is possible that 
some of this variation arose from substitution of 
other varieties by seedsmen, although I have yet 
secured no evidence of any unfair dealing. It is 
possible, also, that the product of some of the 
samples which I early sent out for testing had 
found their way into seedsmen's hands. But I am 



DURATION OF VARIETIES. 125 

convinced that very much of this variation was 
a legitimate result of the various conditions in 
which the crops of 1890 had been grown, and the 
varying ideals of those who saved the seeds. I 
am the more positive of this from the fact that 
the Ignotum tomato, as I first knew it and bred 
it, appears to be lost to cultivation, although the 
name is still used for the legitimate family of 
descendants from my original stock. All this 
experience illustrates how quickly varieties pass 
out by variation and by the unconscious and 
unlike selection practised by different persons. 

The duration of any variety is inversely propor- 
tional to the frequency of its generations. Annual 
plants, other conditions being the same, run out 
sooner than perennials, because seed-reproduc- 
tion — or the generations — intervenes more fre- 
quently. Trees, on the other hand, carry their 
variations longer, because the seed-generations — 
in which departures chiefly take place — are far- 
ther apart. Of all the so-called fruit plants, the 
strawberry runs out soonest and the varieties 
change the oftenest, because a new generation can 
be brought into fruit-bearing in two years, whilst 
it may require a decade or more to bring a new 
generation of apples or chestnuts into bearing. 
Yet, my reader will remind me that the Wilson 
strawberry has been and is the leading variety in 
many places for nearly forty years, to which I 



126 HOAV DOMESTIC VARIETIES ORIGINATE. 

reply that the Wilson of to-day is not necessarily 
the same as that introduced by James Wilson, 
simply because the name is the same. Every dif- 
ferent soil or treatment tends to produce a different 
strain or variation in the Wilson strawberry, as it 
does in any other plant ; and every grower, when 
setting a new plantation, selects his plants from 
that part of his field which pleases him best, 
rather than from those plants which most nearly 
correspond to the original type of the Wilson. 
That is, this unconscious selection on the part of 
the grower takes no account of what the variety 
was, but only of what it ought to be, and this 
ideal differs with every person. It is not surpris- 
ing, therefore, to find strains of Wilson strawberry 
which are as unlike as many named varieties are ; 
and it is to be expected that all of the strains now 
in existence have departed considerably from the 
original type. 

This example borrowed from the strawberry is 
a most important one, because it illustrates how a 
variety may vary and pass out of existence even 
though it is propagated wholly asexually, or by 
buds. There are to-day several different types of 
Rhode Island Greening apple in cultivation, which 
have originated from variations produced by envi- 
ronment and by the different models which propa- 
gators have had in mind ; and the same is true of 
many other fruits. 



AMELIORATION DUE TO SELECTION. 127 

All the foregoing remarks demonstrate the 
importance of constant attention to selection if 
one desires to maintain the exact type of any 
variety which he has produced. They explain 
the value of the "roguing" — or systematic de- 
struction of all " rogues " or non-typical plants — 
which is invariably practised by all good seed- 
growers. But they still more emphatically show 
that every variety is essentially unstable, and that 
the only abiding result is constant evolution, the 
old forms being left behind as the type expands 
into new and better strains. Varieties to be valu- 
able, therefore, ought not to be rigidly fixed, and, 
fortunately, nature has prescribed that they can- 
not be. Probably every decade sees a complete 
change in every variety of any annual species 
which is propagated exclusively from seeds, and 
every century must see a like change in the tree 
fruits. These changes are so gradual, and the 
original basis of comparison fades away so com- 
pletely, that we generally fail to recognize the 
evolution. 

15. It is evident, therefore, that the most abiding 
progress in the amelioration of plants must come as a 
result of the very best cultivation and the most intel- 
ligent selection and change of seed. Every reflec- 
tive person must admit that the cultivation of 
plants — which is the fundamental conception of 
agriculture — has been and is crude and imperfect, 



128 HOW DOMESTIC VARIETIES ORIGINATE. 

and that there has been no conscious effort on the 
part of the human race to produce any given final re- 
sult upon the cultivated flora. Yet, this imperfect 
cultivation has already modified plants so pro- 
foundly that we cannot determine the originals of 
many of them, and we can trace the evolution of 
but few. The science of rural industry is now 
fairly well understood in its essential fundamental 
principles, and the intelligence of those classes of 
persons who deal with plants is rapidly enlarging. 
The opening of the twentieth century will virtu- 
ally mark a new era for agriculture, and from 
that time on the onward evolution of plants should 
proceed confidently and unchecked. Our eyes are 
too often dazzled by the novelties which suddenly 
thrust themselves upon us, and we look for some 
mystic power which shall enable us to produce 
varieties forthwith at our will. We need not so 
much varieties with new names as we do a general 
increase in productiveness and efficiency of the 
types which we already possess ; and this augmen- 
tation must come chiefly in the form of a gradual 
evolution under the stimulus of good care. The 
man who will accomplish most for the amelioration 
and unfolding of the forms of plants, is he who 
fixes his eyes steadily upon the future, and with 
the inspiration of a long forecast, urges the better- 
ment of all conditions in which plants grow. 



DEWBERRY AND BLACKBERRY. 129 

III. Specific Examples. 

The foregoing principles and discussions will 
become more concrete if a few actual examples of 
the origination of varieties are given. In order 
to begin with a very simple case, I will relate the 
introduction of the varieties of dewberries, for 
this fruit is yet little cultivated, the varieties are 
few, and the domestication of it is not yet thirty 
years old. 

The Dewberry and Blackberry* 

The dewberries are native fruits, and it is only 
within the last ten years that they have become 
prominent among fruit-growers. The most impor- 
tant one is the Lucretia. This was found grow- 
ing wild upon a plantation in West Virginia in 
war time. In 1876, a few of the plants were sent 
to Ohio, and from this start the present stock has 
come. It is probable that similar wild varieties are 
growing to-day in many parts of the country, but 
they have not chanced to have been seen by per- 
sons who are interested in cultivating them. It is 
a form of the common wild dewberry, which grows 
all over the northeastern states. Just why this 
particular patch in West Virginia should have been 
so much better than the general run of the species, 
nobody knows, but it was undoubtedly the prod- 
uct of some local environment of soil or position. 

K 



130 HOW DOMESTIC VARIETIES ORIGINATE. 

Early in the seventies, T. C. Bartel, of Huey, 
Clinton Co., Illinois, observed very excellent dew- 
berries growing in rows between the lines of 
stubble in an old cornfield, where the plant had 
evidently been quick to avail itself of unoccupied 
land. This was introduced as the Bartel dew- 
berry, and is now the second in point of promi- 
nence amongst the cultivated varieties. Other 
varieties have appeared in much the same way. 
A fruit-grower in Michigan found an extra good 
dewberry in a neighboring wood-lot, and intro- 
duced it under the name of Geer, in compliment 
to the owner of the place. In Florida, an un- 
usually good plant of the common wild dewberry 
of that region was discovered, and introduced by 
Reasoner Brothers, under the name of Manatee. 
There are now about twenty named varieties of 
dewberries in cultivation, as described in our 
horticultural writings, all of which, so far as I 
know, are chance plants from the wild. 

As the dewberries become more widely grown, 
good seedlings will now and then appear in cul- 
tivated ground, and these will be named and 
sold. After a time persons will begin to sow 
seeds for the purpose of producing new varieties ; 
and those seedlings which chance to possess un- 
usual merit will be propagated, and in due time 
introduced. This is the history of the cultivated 
blackberries and raspberries which have come 



EVOLUTION OF THE APPLE 131 

from the wild plants in less than half a century. 
These fruits are now so far developed that we no 
longer think of looking to the woods and copses 
for new varieties of promise, but the novelties are 
mostly chance seedlings from cultivated varieties. 
A few years ago a friend purchased plants of the 
Snyder blackberry. When they came into bear- 
ing he noticed that one plant was better than the 
rest. It bore larger fruits, and the bearing season 
was longer. He took suckers from this plant, 
and from these others were taken, until he now has 
a large plantation of the novelty, mostly selected 
from plants which pleased him best. The variety 
has such distinct merit that I have named it the 
Mersereau, in honor of the man who recognized 
and propagated it. He will continue selecting 
from the best plants, as he propagates year by 
year, and it may be that in a few years he will 
have so much improved it that it will no longer 
be the variety with which he started. 

The Apple. 

The original apple is not definitely known, but 
it was certainly a very small and inferior, crabbed 
fruit, borne mostly in clusters. When we first 
find it described by historians, it was still of small 
value. Pliny said that some kinds were so sour 
as to take the edge off a knife. But better and 



132 HOW DOMESTIC VARIETIES ORIGINATE. 

better seedlings continued to come up about habi- 
tations, until, when printed descriptions of fruits 
began to be made, three or four hundred years 
ago, there were many named kinds in existence. 
The size had vastly improved, and with this in- 
crease came the reduction of the number of fruits 
in the cluster; so that, at the present time, whilst 
apple flowers are borne in clusters, the fruits are 
generally borne singly. That is, most of the 
flowers fail to set fruit, and they complete their 
mission when they have shed their pollen for the 
benefit of the one which persists. 

The American colonists brought with them the 
staple varieties of the mother countries. But 
the needs of the new country were unlike those 
of the old, and the tastes and fashions of the 
people were changing. So, as seedlings came up 
about the buildings and along the fences, where 
the seeds had been scattered, the ones which prom- 
ised to satisfy the new needs best were saved, and 
many of the old varieties were allowed to pass 
away. In 1817, the date of the first American 
fruit-book, over sixty per cent of the varieties 
particularly recommended for cultivation in this 
country were of American origin. In 1845, 
nearly two hundred varieties of apples were de- 
scribed as having been fruited in this country, 
o*f which over half were of American origin. Be- 
tween these two dates, introductions of foreign 



EVOLUTION OF THE APPLE. 133 

varieties had been freely made, so that the per- 
centage of domestic varieties had fallen. But 
the next thirty years saw a great change. Of 
1823 varieties described in 1872, nearly or quite 
seventy per cent were American, and a still greater 
proportion of the most prized kinds were of 
domestic origin. In the older states, the apple 
had now become so thoroughly accustomed to its 
environment, and the tastes of the people were 
so well supplied, that there was no longer much 
need for the introduction of foreign kinds. It 
was not so in the Northwest. There the apples 
of the eastern states did not thrive. The climate 
was too cold and too dry. Attention was turned 
to other countries with similar or rigorous cli- 
mate. In 1870, the Department of Agriculture 
at Washington imported cions of many varieties 
of apples from Russia; but these did not satisfy 
many fruit-growers of the northern states. It 
was then conceived that the great interior plain 
of Russia should yield apples adapted to the upper 
Mississippi valley, whilst those already imported 
had come from the seaboard territory. Accord- 
ingly, early in the eighties, Charles Gibb, of the 
province of Quebec, and Professor Budd, of Iowa, 
went to Russia to introduce the promising fruits 
of the central plain. The result has been a most 
interesting one to the pacific looker-on. There 
are ardent advocates of the Russian varieties, and 



134 HOW DOMESTIC VARIETIES ORIGINATE. 

there are others who see nothing good in them. 
There are those who believe that all progress 
must come by securing seedlings from the hardi- 
est varieties of the eastern states; there are others 
who would derive everything from the Siberian 
crabs, and still others who believe that the final 
result lies in improving the native crabs. There 
is no end of discussion and cross-purposes. In 
the meantime, nature is quietly doing the work. 
Here is a good seedling of some old variety, there 
a good one from some Russian, and now and then 
one from the crab stocks. The new varieties are 
gradually supplanting the old, so quietly that few 
people are aware of it; and by the time the con- 
testants are done disputing, it will be found that 
there are no Russians and no eastern apples, but 
a brood of northwestern apples which have grown 
out of the old confusion. 

All these new apples are simply seedlings, 
almost all of them chance trees which come up 
here and there wherever man has allowed nature 
a bit of ground upon which to make garden as 
she likes. In 1892, there were 878 varieties of 
apples offered for sale by American nurserymen, 
and it is doubtful if one in the whole lot was the 
result of any attempt on the part of the originator 
to produce a variety with definite qualities. And 
what is true of the apple, is about equally true 
of the other tree fruits. In the small fruits and 



BEANS. 135 

the grapes, where the generations are shorter and 
the results quicker, more has been done in the 
way of direct selection of seeds and the crossing 
of chosen parents; but even here, the methods 
are mostly haphazard. 

Beans. 

Perhaps there are no plants more tractable in 
the hands of the plant-breeder than the garden 
beans. Some two or three years ago, a leading 
eastern seedsman conceived of a new form of bean 
pod which would at once commend itself to his 
customers. He was so well convinced of the 
merits of this prospective variety, that he made 
a descriptive and " taking " name for it. He then 
wrote to a noted bean-raiser, describing the pro- 
posed variety and giving the name. " Can you 
make it for me ? " he asked. " Yes, I will make 
you the bean," replied the grower. The seeds- 
man then announced in his catalogue that he 
would soon introduce a new bean, and, in order 
to hold the name, he published it, along with the 
announcement. Two years later, I visited the 
bean-grower. " Did you get the bean ? " I asked. 
"Yes, here it is." Sure enough, he had it, and it 
answered the requirements very well. Another 
seedsman would like a round-podded, stringless, 
green-podded bean. This same man produced 



136 HOW DOMESTIC VARIETIES ORIGINATE. 

it, and I went into a field of fifteen acres of it, 
where it was growing for seed, and the most fas- 
tidious person could not have asked for a closer 
approach to the ideal which the breeder had set 
before him some four or five years before. 

How is all this done ? It looks simple enough. 
The ideal is established first of all. The breeder 
revolves it in his mind, and eliminates all the 
impracticable and contradictory elements of it. 
Then he goes carefully and critically through his 
bean fields, particularly those varieties which are 
most like the desired kind, and marks those plants 
which most nearly approach his ideal The seeds 
of these are carefully saved, and they are planted 
in isolated positions. If he finds no promising 
variations amongst his plantations, then he must 
start off the variation in some other way. This 
is usually done by crossing those varieties which 
are most like the proposed kind. He has got a 
start ; but now the science and skill begin. Year 
by year he selects just those plants which please 
him best and which he judges, from experience, 
will most surely carry their features over to the 
offspring. He starts with one plant ; the next 
year he may have only two. If he has ten or 
twenty good ones, then the task is an easy one, 
for the variety has elements of permanence — that 
is, of hereditability — in it. But he may have no 
plants the second year. In that case, he begins 



BEAKS. 137 

again ; for if the ideal is true, it can be attained. 
This bean-breeder to whom I have referred, and 
upon whom many of our best seedsmen rely for 
new varieties, tells me that he has discarded fully 
three thousand varieties and forms as profitless. 
This only means that he is a most astute judge 
of beans, and that he knows when any type is 
likely to prove to be a poor breeder. 

The bean also affords an excellent example of 
the care which it is generally necessary to exercise 
to keep any variety true to the type. The person 
of whom I have spoken, in common with all care- 
ful seed-growers, searches his field with great 
pains to discover the "rogues," or those plants 
which vary perceptibly from the type of the given 
variety. The rogue may be a variation in size or 
habit of plant, season of maturity, color or form 
of pods, productiveness, susceptibility to rust, or 
other aberrance. In the dwarf or bush beans, 
which are now most exclusively grown, the most 
frequent rogue is a climbing or half-climbing 
plant. This is a reversion to the ancestral type 
of the bean, which was no doubt a twining plant. 
This rogue is always destroyed, even though it 
may be, itself, a good bean. In some cases, the 
men who perform the roguing are sent along 
every row of a whole field on their hands and 
knees, critically examining every plant. The ef- 
fect of this continual selection is always to push 



138 HOW DOMESTIC VARIETIES ORIGINATE. 

on the variety to greater excellence. The vari- 
ous " improved " strains of plants are obtained in 
essentially this fashion. If the grower has been 
painstaking with his roguing, he soon finds that 
his seed gives better and more uniform crops than 
the common stock of the variety. If the improve- 
ment is marked, he may dignify his strain with 
a distinct name, and it thereby becomes a new 
variety. The improvement may be a very im- 
portant one to a careful bean-grower, and at the 
same time be so slight as to escape the attention 
of the general farmer, or even of experimenters 
who are not particularly skilled in judging the 
merits of beans. 

All these examples drawn from the bean are 
excellent illustrations of the best and most scien- 
tific plant-breeding, and the same methods — varied 
to suit the different needs — apply to the ameliora- 
tion of all other plants. The recent dwarf Lima 
beans may be cited as examples of accidental or 
fortuitous varieties, in which the preconstructed 
ideal of the plant-breeder had no place. Four or 
five of these beans have attained some prominence. 
Henderson and Kumerle dwarf Limas were intro- 
duced in 1889, Burpee in 1890, and Barteldes in 
1892 or 1893. The variety which is now called 
the Henderson was picked up twenty or more 
years ago by a negro, who found it growing along 
a roadside in Virginia. It was afterwards grown 



BEANS. 139 

in various gardens, and about 1885 it fell into the 
hands of a seedsman in Richmond. Henderson 
purchased the stock of it in 1887, grew it in 
1888, and offered it to the general public in 1889. 
The introduction of Henderson's bean attracted 
the attention of Asa Palmer, of Kennett Square, 
Pennsylvania, who had also been growing a dwarf 
Lima. He called upon Burpee, the well-known 
seedsman of Philadelphia, described his variety, 
and left four beans for trial. These were planted 
in the test grounds and were found to be valuable. 
Mr. Palmer's entire stock was then purchased, — 
comprising over an acre, which had been carefully 
inspected during the season — and Burpee Bush 
Lima was presented to the public in the spring of 
1890. Mr. Palmer's dwarf Lima originated in 
1883, when his entire crop of Large White (Pole) 
Limas was destroyed by cut- worms. He went 
over his field to remove the poles before fitting 
the land for other uses, but he found one little 
plant, about ten inches high, which had been cut 
off about an inch above the ground but which had 
re-rooted. It bore three pods, each containing one 
seed. These three seeds were planted in 1881, 
and two of the plants were dwarf, like the parent. 
By discarding all plants which had a tendency to 
climb, in succeeding crops, the Burpee Bush Lima, 
as we now have it, was developed. The Kumerle, 
Thorburn, or Dreer, Dwarf Lima originated from 



140 HOW DOMESTIC VARIETIES ORIGINATE. 

occasional dwarf forms of the Challenger Pole 
Lima, which J. W. Kumerle, of Newark, New 
Jersey, found growing in his field. The stock 
which came from these selected dwarf plants was 
introduced by Thorburn and Dreer, under their 
respective names. The singular Barteldes Bush 
Lima came from Colorado, and is a similar dwarf 
sport of the old White Spanish or Dutch Runner 
bean. Barteldes received about a peck of the 
seed and introduced it sparingly. It attracted 
very little attention, and as the following season 
was dry, Barteldes himself failed to get a crop, 
and the variety was lost to the trade. 

Carinas. 

Few plants have shown more remarkable evolu- 
tions in very recent years than the cannas. At 
the present time, the Crozy cannas — so named 
from Crozy, of Lyons, France, who has introduced 
the greater number of them — are most popular. 
This type is often called the French Dwarf, or 
the Flowering Canna, and it is marked by a com- 
paratively low stature, and very large and showy 
spreading floAvers in many colors, whereas the can- 
nas of a few years ago were very tall plants, with 
small and late dull red, narrow flowers, and they 
were grown exclusively for their foliage effects. 
How has this transformation come about? 



C ANN AS. 141 

In the first place, it should be said that there 
are many species of canna, and about a half dozen 
of these were well known to gardeners at the 
opening of the century. About 1830, the cannas 
began to attract much attention from cultivators, 
and the original species were soon variously hybrid- 
ized. Crossed seeds, and seeds from the succes- 
sive generations of hybrids, introduced a host of 
new and variable forms. The first distinct fash- 
ion in cannas seems to have been for tall, late- 
flowering forms. In 1848, Annee, a cultivator in 
France, sowed seeds of Canna Nepalensis, a tall 
oriental species, and there sprung up a race of 
plants which has since been known as Canna 
Annsei. It is probable that this Canna Nepalensis 
had become fertilized with other species growing 
in Annee's collection, very likely with Canna 
glauca. At any rate, this race of cannas became 
popular, and was to its time what the French 
dwarfs are to the present day. The plants were 
freely introduced into parks, beginning about 
1856, but their use began to wane by 1870 
or before. Descendants of this type, variously 
crossed and modified, are now frequently seen 
in parks and gardens. 

The beginning of the modern race of dwarf," 
large-flowered cannas was in 1863, when one of 
the smaller-flowered Costa Rican species (Canna 
Warscewiczii) was crossed upon a large-flowered 



142 HOW DOMESTIC VARIETIES ORIGINATE. 

Peruvian species (Canna iridiflora) . The off- 
spring of this union came to be called Canna 
Ehemanni. This hybrid has been again variously 
crossed with other species, and modified by culti- 
vation and selection, until the present composite 
type is the result. Seeds give new varieties; and 
any seedling which is worth saving is thereafter 
multiplied by divisions of the root, and the result- 
ing plants are introduced to commerce. 

These various examples are but types of what 
has been and can be accomplished in a given group 
of plants. There is nothing mysterious about the 
subject, so far as the cultivator is concerned. He 
simply sets his ideal, makes sure that it does not 
contradict any of the fundamental laws of devel- 
opment of the plant with which he is to work, 
then patiently and persistently keeps at his task. 
He must have good judgment, skill, and inspira- 
tion, but he does not need genius. 

u In the improvement of plants," writes Henri 
L. de Vilmorin, "the action of man, much like 
influences which act on plants in the wild state, 
only brings about slow and gradual changes, often 
scarcely > noticeable at first. But if the efforts 
toward the desired end be kept on steadily, the 
changes will soon become greater and greater, and 
the last stages of the improvement will become 
much more rapid than the first ones." 



LECTURE IV. 

RECENT OPINIONS: BEING A RESUME OP THE 
INVESTIGATIONS OF DE VRIES, MENDEL, AND 
OTHERS, AND A STATEMENT OF THE CURRENT 
TENDENCIES OF AMERICAN PLANT-BREEDING 
PRACTICE. 

In the first and second editions, Lecture IV. was 
devoted to " Borrowed Opinions," being extracts 
from representative European writings. The chap- 
ter contained a conspectus of Verlot's opinions re- 
specting the production of varieties, as expressed 
in his "Sur la Production et la Fixation des vari- 
etes dans les Plantes d'Ornement"; also a rather 
full transcript of Carriere's account of bud-varie- 
ties from his " Production et Fixation des Vari- 
etes dans les Vegetaux " ; and a translation of 
Focke's discussion of the characteristics of crosses 
from Chapter IV. of "Die Pflanzen-Mischlinge." 
Since 1895 a very great change of view has taken 
place in respect to all the matters discussed in 
those papers, although the vexed questions asso- 
ciated with bud- variation are not yet greatly elu- 
cidated. It has seemed best, therefore, to devote 
this chapter now to the recent opinions rather 
than to the older opinions. The idea of the " fixa- 
tion of varieties " — as a chemist might speak of 

143 



144 RECENT OPINIONS. 






the fixation of gases or other substances — will not 
apply to plants. In fact, the production of mere 
"varieties" is a passing ideal, for we are now 
endeavoring to produce characters or units. 
Varieties are not entities, or real units. The 
point of emphasis has shifted. It is suggestive 
that the term "plant-breeding," rather than the 
"production of varieties,** is now current, indicat- 
ing that we now conceive primarily of a process : 
this process, when intelligently followed, may pro- 
duce plants of new value. 

I. Some Recent Ideas on the Evolution 
of Plants. 1 

There is endless dissimilarity in nature. No 
two plants and no two animals are exactly alike. 
There are more plants and animals than can find 
a place in which to live and thrive. There results 
a struggle for existence. Those animals or plants 
which, by virtue of their individual differences or 
peculiarities, are best fitted to the conditions in 
which they are placed, survive in this struggle for 
existence. They are " selected " to live. Those 
that survive, propagate their peculiarities. By 

1 Address before the Society for Plant Morphology and Physi- 
ology, Washington, December 20. 1902. Printed in Science, 
March 20, 1903, but now somewhat modified. The greater part 
of this essay that relates to the De Vriesian views was read and 
corrected in the manuscript by Professor de Vries. 



EVOLUTION OF PLANTS. 145 

virtue of continued variation, and of continual se- 
lection along a certain line, the peculiarities may 
become augmented ; finally the gulf of separation 
from the parental stem becomes great, and what 
we call a new species has originated. 

This, in epitome, is the philosophy of Darwin 
in respect to evolution of organic forms. It con- 
tains the well-known postulate of natural selec- 
tion, the principle that we know as Darwinism. 
This principle has had more adherents than any 
other hypothesis of the process of evolution. All 
recent hypotheses in some way relate to it. A 
number of them modify it, and some dispute it. 
The most pronounced counter-hypothesis is also 
the newest. It is that of Professor de Vries, 
botanist, of Amsterdam, who denies that natural 
selection is competent to produce species, or that 
organic ascent is the product of small differences 
gradually enlarging into great ones. According 
to De Vries's view, species-characters arise sud- 
denly, or all at once, and they are ordinarily stable 
from the moment they arise. 

a. Variation: De Juries. 

De Vries conceives that variations, or differ- 
ences, are of two general categories: (1) Va- 
riation proper, or small, fluctuating, unstable 
differences peculiar to the individual (only par- 



146 RECENT OPINIONS. 

tially transmitted to offspring); and (2) muta- 
tions, or differences that are usually of marked 
character, appear suddenly and without transition 
to other forms and are at once the starting-points 
of new races or species. Variations proper may 
be due to the immediate environment in which the 
plant lives. m The mutations are due to causes yet 
unknown, although these causes are considered to 
be physiological. 

Natural selection works on both variations and 
mutations by eliminating the forms that are least 
adapted to persist. It is conceived to be a de- 
structive, not a constructive or augmentative 
agency. It merely weeds out. 

We may first consider selection with reference 
to variations proper. Among variations, or indi- 
vidual fluctuations, there may be a slight cumula- 
tive effect of selection, but it is incompetent ever 
to enlarge the differences into stable character- 
istics ; and when natural selection ceases to act, 
the so-called variety falls back into its original 
form or splits up into other forms. Varieties 
of this kind are notably indefinable and unstable. 
It is impossible to " fix " them in any true sense ; 
selection only preserves them, and when it is 
removed they perish as varieties. They are rela- 
tively only temporary and have no effect on phy- 
logeny. Many of the minor adaptations of plants 
to the particular conditions in which they chance 



EVOLUTION OF PLANTS. 147 

for the time being to be placed, are of this category. 
Much of the variation which results in acclimati- 
zation belongs here. The fluctuating horticul- 
tural varieties and gardeners' " strains " are of 
this kind. This discussion of the effect of cessa- 
tion of selection recalls Weismann's panmixia, a 
name proposed to designate the breaking up of 
varietal or specific characteristics when natural 
selection ceases to act. Panmixia is not of itself 
an original force or an agency ; it is merely a 
name for the results of all the forces or energies 
which are allowed to assert themselves when the 
restricting force of natural selection is removed. 
In De Vries's view, the progress made by selection 
must be maintained by selection. 

We may next consider selection with reference 
to mutations. The mutations are practically stable 
or "fixed" the moment they arise. Of course 
there may be individual fluctuations or variations 
proper, amongst plants that have sprung from a 
mutated individual ; but the main characteristics 
of the mutations are heritable. An organism is a 
complex of organs and attributes. Each attribute 
is a unit. From any unit a new unit may arise 
by mutation. The origination of a new unit con- 
stitutes at once a full and important character and 
marks the organism that possesses it as a new 
physiological species. Not only one unit, but any 
number of units, may give rise to mutations ; and 



148 



RECENT OPINIONS. 



any one of these new mutations may give rise to 
other mutations. But the point is, that these 
mutations, be they great or small, arise by steps, 
are full formed when they arise, and do not grow 
or enlarge into other mutations. The mutations 
are multifarious (aU-seitig), occurring apparently 
at random and in diverse directions, and with- 
out regard to fitness. They may be either quan- 
titative or qualitative. Variations proper arise 
mostly in a definite line. Now, natural selection 
may weed out mutated individuals as it does mere 
variant individuals ; and thus breaks may arise 
in the chain, and we have left what we know as 
taxonomic species. 

Natural selection, with survival of the fittest, is, 
therefore, of two categories, at least so far as results 
are concerned, — that which operates within the 
species and results in the formation of local minor 
races, and that which operates between species and 
results in the formation of a line of ascent. 

Everywhere and always plants are variable. 
Now and then and relatively rarely, plants are 
mutative. Any man who sees two plants, sees 
variation : there are no two plants alike. Only 
he who studies and observes critically, sees muta- 
tion. One must examine a hundred or a thou- 
sand or ten thousand individuals. In De Vries's 
extended experiments with (Enothera, only 1.5 
per cent of the plants were mutative, and muta- 



EVOLUTION OF PLANTS. 149 

tion is undoubtedly more common in cultivation 
than in the wild, and the mutated individuals are 
more likely to persist. The investigator should 
employ only statistical methods of comparison. 
He should contrast unit-characters rather than in- 
dividuals as a whole. Moreover, not only are the 
numbers of mutating individuals relatively uncom- 
mon, but the species may not now be in a muta- 
tive epoch. 

In other words, there are epochs in the history 
of the plant when mutations occur. These are 
the "mutation-periods" of De Vries. There are 
epochs of non-mutations, when no progress seems 
to be making. It may be conceived that some 
force is withholding or restraining the mutative 
impulse. This force is what we are in the habit 
of calling heredity. When heredity is overcome, 
there arises a "premutation- period," in which the 
mutations are beginning to express themselves ; 
and eventually the full mutation-period may ap- 
pear. Heredity and non-heredity, these are the 
ever opposing and ever contrasting forces in or- 
ganic life, the one resulting in the survival of the 
like, the other resulting in the survival of the 
unlike. One is heredity; the other is variation. 
One makes for continuity ; the other for evolution. 
No hypothesis of the energy of evolution is per- 
fect that does not account for both. A theory of 
heredity, or continuity, must also account for the 



150 RECENT OPINIONS. 






opposite of itself. It is not easy to construct a 
hypothesis or a metaphor that will accomplish this. 

The phenomena of continuity and discontinuity 
were well contrasted by Korschinsky. These 
phenomena, he conceived, are the results of two 
antagonistic tendencies. Under normal or usual 
conditions heredity is the stronger force. The 
tendency to vary is always present, being predis- 
posed by environment but not caused by it ; when 
it gathers the necessary energy it overbreaks the 
power of inheritance and sudden variations or 
sports arise, and these sports are the starting- 
points of evolution. This discontinuous evolu- 
tion is called by him heterogenesis. 

The conceptions of per saltum variations of 
Korschinsky and De Vries seem to be practically 
identical. De Vries has carried his work further, 
into the realm of actual experimental investiga- 
tion. He studied many species of plants in the 
hope of finding one or more that might be in its 
mutation-period. Finally, he chose the common 
evening primrose, (Enothera Lamarckiana, and by 
continual sowing of seeds and raising of great 
numbers of plants he discovered several truly 
mutative forms. These forms reproduce them- 
selves by means of seeds as accurately as accepted 
species do. He has given some of them specific 
names. The full experimental history of them is 
given in the first volume of his brilliant work, 



EVOLUTION OF PLANTS. 151 

"Die Mutationstheorie." These forms, he con- 
tends, are true elementary species. That is, they 
have new specific characters. These characters 
are heritable. It does not matter whether these 
characters are large or small — they become phylo- 
genetic. These plants having the new specific 
characters may not be species in the Linnaean or 
historic or morphological sense, but they are real 
entities. We must give up the historical view of 
species when we study the evolution of organic 
forms. Historic or Linneean species are taxonomic 
conceptions ; the evolutional or elementary spe- 
cies are physiological conceptions. 

The different categories of species, as respects 
their origin, are given as follows by De Vries : — 

A. Origin by means of formation of new char- 

acters, or progressive species-origin. 

B. Origin without formation of new characters. 

1. By the becoming latent (latentwerdeii) of 

present characteristics, or retrogressive 
species-origin. Atavism in part belongs 
here. 

2. By the becoming active (activirung) of 

latent characteristics, or degressive spe- 
cies-origin [degress, to come down from, 
to come out of] . 

(a) Taxonomic anomalies. 

(b) True atavism. 

3. By means of hybrids. 



152 RECENT OPINIONS. 

It will now be seen that the mutation theory of 
De Vries, which is in some respects a rephrasing 
and an extending of the old idea of sports, does 
not of itself introduce any new theory of the 
dynamics of evolution. It is not a theory of 
heredity nor of variation. His hypothesis of " in- 
tracellular pangenesis " carries the explanation of 
these phenomena one step further back, however. 
The plant cells give off pangenes. Each of these 
pangenes divides into two. Ordinarily, these two 
resemble the parent ; but now and then one of 
them takes on a new character — the two become 
unlike — and gives rise to a mutation. This hy- 
pothesis, like Darwin's pangenesis, is useful as a 
graphic basis for discussion, whether or no it has 
real physiological foundation. 

The most emphatic points of the mutation 
theory as they appeal to me are these : (1) It 
classifies variation into kinds that are concerned 
in evolution and kinds that are not ; and thereby 
it denies that all adaptation to environment makes 
for the progress of the race. (2) It denies the 
power of natural selection to fix, to heap up, or 
to augment differences until they become truly 
specific. (3) It separates the results of struggle 
for existence and survival of the fittest into two 
categories, only one of which has an effect on 
phylogeny. (4) It asserts that evolution takes 
place by steps, and not by a gradual unfolding of 



EVOLUTION OF PLANTS. 153 

one form into another, — that it is discontinuous 
rather than continuous. (5) It enforces the im- 
portance of critical comparative study of great 
numbers of individuals. (6) It challenges the 
validity of the customary conception of species as 
competent to elucidate the method of evolution. 

There will arise confusion, in the forthcoming 
discussions of the theory of discontinuity, as to 
what is a species ; but this confusion is not new. 
There are two conceptions of species: (1) As 
taxonomic groups, more or less arbitrarily made 
for purposes of classification ; (2) as real things, 
marked by recordable differences however small 
or great, and conceived to be the actual steps in 
the phylogeny of the race. These categories are 
so distinct that they would not be confounded ex- 
cept for the unfortunate circumstance that we use 
one word (species) for the two. There has been 
a growing conviction that the two classes must be 
sharply separated when evolution questions are 
discussed. Nearly ten years ago I endeavored to 
combat the species-dogma from the garden point 
of view, as, in differing ways, others had done be- 
fore (" Survival of the Unlike," Essay IV.). The 
confusion of the two conceptions expresses itself 
in the terminology of plant-breeding. Some writ- 
ers define hybrid, for example, as a cross between 
species ; this is the classificatory idea. Others 
define it to be any cross. The former use of the 



154 RECENT OPINIONS. 

word is more proper merely because it is the his- 
toric use, originating as a systematist's concept. 
The latter idea should have been expressed by a 
new word. It is for this reason that I have held 
to the old or systematic definition of hybrid ; but 
there is no appeal against usage, so, while still 
proclaiming the righteousness of my cause as an 
easement of my conscience, I strike my colors and 
henceforth use the word hybrid for a cross of any 
kind or degree. How often does mere language 
confuse us ! 

From an argumentative point of view, it will be 
difficult to determine, in a given case, just what 
are variations and what mutations, for these cate- 
gories are separated not by any quantitative or 
qualitative characters — the " step " from one to 
the other may be ever so slight — but by the test 
that one kind is fully heritable and the other only 
partially so. If a mutation is to be defined as a 
heritable form, then it will be impossible to con- 
trovert the doctrine that evolution takes place by 
mutation, because the mutationist can say that any 
form that is inherited is by that fact a mutation. 
This will be equivalent to the position of those 
who, in the Weismannian days, denied the trans- 
mission of acquired characters, but defined an 
acquired character to be one that is not transmis- 
sible. However, it is to be hoped that the dis- 
cussion of the mutation theory will not degenerate 



EVOLUTION OF PLANTS. 155 

into a mere academic debate and a contention over 
definitions. Professor de Vries himself has set 
the direction of the discussion by making actual 
experiments the test of the doctrine. There will 
be confusing points, and times when we shall dis- 
pute over particular' forms as to whether they are 
variations or mutations ; but every one who has 
studied plants from the evolution point of view 
will be prepared to believe that species do origi- 
nate by mutation. De Vries's work will have a 
profound and abiding influence on our evolution 
philosophies. For myself, I am a Darwinian, but 
I hope that I am willing to believe what is true, 
whether it is Darwinian or anti-Darwinian. My 
own belief is that species do originate by means 
of natural selection, but that not all species so 
originate. 

b. Heredity : Mendel. 

De Vries made a thorough search of the litera- 
ture of plant evolution. In an American publica- 
tion 1 he saw a reference to an article on plant 

1 The following extract from a recent letter from Professor 
de Vries (printed here by permission) will explain the refer- 
ence in the text: "Many years ago you had the kindness to 
send me your article on Cross-Breeding and Hybridizing of 1892; 
and I hope it will interest you to know that it was by means of 
your bibliography therein that I learnt some years afterwards 
of the existence of Mendel's papers, which now are coming to 
so high credit. Without your aid I fear I should not have found 



156 RECENT OPINIONS. 

hybrids by G. Mendel, published in 1865 in the 
proceedings of a natural history society of Brunn 
in Austria. On looking up this paper he was 
astonished to find that it discussed fundamental 
questions of hybridization and heredity, and that 
it had remained practically unknown for a genera- 
tion. In 1900 he published an account of it, and 
this was soon followed by independent discussions 
by Correns, Tschermak, and Bateson. In May, 
1900, Bateson gave an abstract of Mendel's work 
before the Royal Horticultural Society of Eng- 
land ; and later the society published a translation 
of Mendel's original paper. It is only within the 
present year, however (1902), that a knowledge 
of Mendel's work has become widespread in this 
country. Perhaps the agencies that are most 
responsible for dissemination of the Mendelian 
ideas in America are the instruction given by 
Webber and others in the Graduate School of 
Agriculture at Columbus last summer, and the 
prolonged discussion before the International 
Conference on Plant-Breeding at New York last 
fall (1902). Lately, several articles on the sub- 
ject have appeared from our scientific press. 

them at all." My reference to Mendel in the bibliography- 
referred to was taken from Focke's writing. I had not seen 
Mendel's paper. The essay, " Cross-Breeding and Hybridizing," 
forms Chapter II. of the present book ; but the bibliography that 
accompanied it was not reprinted until the second edition of the 
book. 



EVOLUTION OF PLANTS. 157 

Mendel's work is important because it cuts 
across many of the current notions respecting 
hybridization. As De Vries's discussions call a 
halt in the current belief regarding the gradual- 
ness and slowness of evolution, so Mendel's call 
a halt in respect to the common opinion that the 
results of hybridizing are largely chance, and that 
hybridization is necessarily only an empirical sub- 
ject. Mendel found uniformity and constancy of 
action in hybridization, and to explain this uni- 
formity he proposed a theory of heredity. 

One of the most significant points connected 
with Mendel's work is the great pains he took to 
select plants for his experiments. He believed 
that hybridism is a complex and intricate subject, 
and that, if we are ever to discover laws, we must 
begin with the simplest and least complicated 
problems. He was aware of the general belief 
that the most diverse and contradictory results 
are likely to follow any hybridization. He con- 
ceived that some of this diversity may be due to 
instability of parents rather than to the proper 
results of hybridizing. He also saw that he must 
exclude all inter-crossing in the progeny. Fur- 
thermore, the progeny must be numerous, for, 
since incidental and aberrant variation may arise 
in the plants, it is only by a study of averages of 
large numbers that the true results of the hybrid- 
izing are to be discovered. Moreover, the study 



158 RECENT OPINIONS. 

must be more exact than a mere contrasting and 
comparing of plants : character must be compared 
with character. 

The garden pea seemed to fulfil all the require- 
ments. Mendel chose well-marked horticultural 
races or varieties. These he grew two years 
before the experiment proper was begun in order 
to determine their stability or trueness to type. 
When the experiments were finally begun, he 
used only normal plants as parents, throwing out 
such as were weak or aberrant. Peas are self- 
fertile. It was to be expected that under such 
conditions the hybrid offspring would show uni- 
formity of action ; and it did. 

In order to study the behavior of the hybrids, it 
was necessary to choose certain prominent marks 
or characters for comparison. Seven of these 
characters were selected for observation. These 
marks pertain to seed, fruit, position of flowers, 
and length of stem, and they may be assumed to 
be representative of all other characters in the 
plant. These characters were paired (practically 
opposites), as long-stem vs. short-stem, round-seed 
vs. angular-seed, inflated-pod vs. constricted-pod. 
They were "constant" and "differentiating." Of 
course every parent plant possessed one or the 
other of every pair of contrasting characters; but 
in order to facilitate his studies, Mendel chose a 
special set of parents to illustrate each character, 



EVOLUTION OF PLANTS. 159 

studying seecl-shape in one set of hybrids, seed- 
color in another, pod-shape in another; in this 
way he avoided complication in the results. Since 
it is not my purpose to discuss Mendel's work 
in detail, but only the general significance of its 
results, as they appeal to me, I need not describe 
these characters here. It will be sufficient if I 
choose only one, the shape of the seed. 

The seed-shape characters were roundness and 
angularity — the former being the " smooth " pea 
of gardeners and the latter the " wrinkled " pea. 
Let us suppose that twenty-five flowers on round- 
seeded plants were cross-pollinated in the summer 
of 1900 with pollen from angular-seeded plants, 
or vice versa, and that an average of four seeds 
formed in each pod. With the death of the 
parent plants the old generation ended, and the 
100 seeds that matured in 1900 — the year in 
which the cross was made — began the next gen- 
eration ; and these 100 seeds were hybrids. Now, 
all these 100 seeds were round. Roundness in 
this case was "dominant." (Dominance pertain- 
ing to the vegetative stage of the plant of course 
would not appear until 1901, when the seeds 
"grow.") These seeds are sown in the spring 
of 1901. If each seed be supposed to give rise to 
four seeds — or 400 in all — this next generation 
of seeds (produced in 1901) will show 300 round 
and 100 angular seeds. That is, the other seed- 



160 RECENT OPINIONS. 

shape dow appears in one-fourth of all the prog- 
eny; this character is said to have been u reces- 
sive" in the first hybrid generation. If the 100 
angular seeds, or recessives, are sown in 1902, it 
will be found that all the progeny will be angular- 
seeded or will " come true " ; and this occurs in 
all succeeding generations providing no crossing 
takes place. If the 300 round seeds, or domi- 
nants, are sown in the spring of 1902, it will be 
found that 100 of them produce dominants only, 
and that 200 of them behave as before — one- 
fourth giving rise to recessives and three-fourths 
to dominants ; and this occurs in all succeeding 
generations providing no crossing takes place. In 
other words, the three-fourths of dominants in 
any generation are of two kinds, — one-third that 
produce only dominants, and two-thirds that are 
hybrids. That is, there is constantly appearing 
from the hybrids one-fourth part that are re- 
cessives, one-fourth part that are constant domi- 
nants, and one-half part that are dominants to 
all appearances, but which in the next genera- 
tion break up again into dominants and reces- 
sives. This one-half part that breaks up into the 
two characters are the true hybrids ; but they 
are hybrids only in the sense that they hold each 
of the two parental characteristics — roundness 
and angularity — in their purity and not as blends 
or intermediates ; and these two characteristics 



EVOLUTION OF PLANTS. 



161 



reappear in all succeeding generations in a definite 
mathematical ratio. Proportionally, these facts 
may be expressed as follows : — 

1900. 1901. 1902. 1903. 

4 D 16 D 



1 seed 




It will be seen that two-thirds of the dominants 
break up the following year into one-fourth con- 
stant dominants, one-fourth recessives, and one- 
half that again break up, the half that break up 
being the hybrids. This formula for the hybrids 
is Mendel's law. In words, it may be expressed 
as follows : Differentiating characters in plants 
reappear in their purity and in mathematical regu- 
larity in the second and succeeding hybrid off- 
spring of these plants ; the mathematical law is 
that each character separates in each of these gen- 
erations in one-fourth of the progeny and there- 
after remains true. In concise figures, it is 
expressed as follows : 

1D:2DB:1 B. 



M 



162 RECENT OPINIONS. 

ID and IE come true, but BR breaks up again 
into dominants and recessives in the ratio of 3 to 1. 

Mendel found that this law holds more or less 
for the other characters that he studied in the pea, 
as well as for the seed-shape. He did not con- 
clude, however, that it holds good for all plants, 
but left the subject for further investigation. He 
himself found different results in Hieracium. It 
will be seen at once that it will be a very difficult 
matter to follow this law when many characters 
are to be contrasted, particularly when the char- 
acters are merely qualitative and grade into each 
other. 

The dominant characters pertain to either 
parent : some of them may come from the mother 
and some from the father. When this roundness 
is dominant from the male parent, it falls under 
the domination of what we commonly know as 
xenia, or the immediate effect of pollen ; when it 
is from the female parent, there is no xenia. In 
the case of the pea, the seed-content is embryo 
and we are not surprised if there is xenia. In 
those plants in which the embryo is embedded in 
endosperm, however, it would seem to be difficult 
to account for xenial dominance, unless there is 
double fecundation, as appears to be the case in 
Indian corn, as pointed out by De Vries, Webber, 1 

1 Bull. 22, Div. of Veg. Phys. and Path., U. S. Dept. Agric, 
1900. 



EVOLUTION OF PLANTS. 163 

and others. It looks as if the question of domi- 
nance would introduce a new point of view into 
the study of xenia. At all events, the word xenia 
must be very clearly re-defined. There is now a 
strong tendency to restrict the use of the word to 
designate only those effects occurring in parts 
lying outside the embryo. 

Which characters will be dominant in any spe- 
cies we cannot determine until we perform the 
experiment ; that is, there is no mark or attribute 
which distinguishes to us a 'priori a dominant 
or a recessive character. However, the mere fact 
as to whether the one or the other character is 
dominant is relatively unimportant, for constant 
dominance is no more a regular behavior than 
recessiveness is. In various subsequent experi- 
ments it has been found that even when marked 
dominance is not shown in the first product, the 
hybridization may follow the law in essential 
numerical results. The really important points 
are: (1) That the characters typically remain 
pure or do not blend, and (2) that their reappear- 
ance follows a numerical order. 

After finding such surprising results as these, 
Mendel naturally endeavored to discover the rea- 
sons why. The product of his speculations is the 
theory of gametic purity (to use our present-day 
terminology), which is a partial theory of heredity. 
Every plant is the product of the germ or female 



164 RECENT OPINIONS. 

cell fertilized by the sperm or male cell. When 
constant progeny is produced it must be because 
the two cells, or gametes, are of like character. 
When inconstant progeny is produced, it must be 
because the sperm cell is of one character and the 
germ cell of another. When these unlike gametes 
come together they will unite according to the 
law of mathematical probabilities, one-fourth of 
those of each kind coming together and one-half 
of those of both kinds coining together. If A and 
B represent the contrasting parental characteris- 
tics, they would combine as — 

A + A = A 2 
A + B = AB 
B + A = BA 
B+ B = B 2 

A 2 and B 2 are equivalent only to A and B. 

Since both of the opposed or contrasted characters 

cannot be visible at the same time, we have the 

following : — 

A 
A* 
A h 
B 

in which small b represents the character that for 
the time being is not able to express itself, or is 
recessive, and large B represents the same charac- 
ter fully expressed. 

In these gametes the unit characters of the 
plants that bear them are pure. Even in hybrid 



EVOLUTION OF PLANTS. 165 

plants the pollen grains and the egg cells are not 
hybrids. According to this hypothesis of gametic 
purity, therefore, hybrids follow natural and numer- 
ical laws ; but these laws are always obscured by 
new crossing. True intermediate characters do 
not occur. If new characters appear, it is because 
they have been recessive or latent for a genera- 
tion, or because the plant has varied from other 
causes ; they are not the proper results of hybridi- 
zation. We may suppose that a new character 
that appears because of effect of environment may 
be impressed on the gamete and thereby be perpet- 
uated. The results of hybridization, according to 
the Mendelian view, are not fundamentally a mere 
game of chance, but follow a law of regularity of 
averages ; but the results are so often masked 
that it is sometimes impossible to recognize the law. 
It is a question, of course, whether the propor- 
tional results secured by Mendel and others express 
a biological principle, or whether they are onhy the 
numerical proportions that may be adduced from 
the averages of large numbers of combinations — 
whether these combinations are of gametes, or let- 
ters, or words, or figures. It is a fundamental 
necessity that certain proportions follow from 
" chance " combinations often repeated. But 
whether the " theorem of probabilities" can express 
a real biological fact may well be doubted. Per- 
haps the basis of heredity is of a very different 



166 RECENT OPINIONS. 

order from the mechanico-physical conceptions 
that we habitually apply to it. 

Mendel's law of heredity is recently stated as 
follows by Bateson and Saunders : " The essential 
part of the discovery is the evidence that the germ- 
cells or gametes produced by cross-bred organisms 
may in respect of given characters be of the pure 
parental types and consequently incapable of 
transmitting the opposite character; that when 
such pure similar gametes of opposite sexes are 
united together in fertilization, the individuals so 
formed and their posterity are free from all taint 
of the cross ; that there may be, in short, perfect 
or almost perfect discontinuity between these 
germs in respect of one of each pair of opposite 
characters." 

This, in barest epitome, is the teaching of Men- 
del. This teaching strikes at the root of two or 
three difficult and vital problems. It presents a 
new conception of the proximate mechanism of 
heredity, although it does not present a complete 
hypothesis of heredity since it begins with the 
gametes after they are formed and does not ac- 
count for the constitution of the gametes, nor the 
way in which the parental characters are impressed 
upon them. This hypothesis will focus our atten- 
tion along new lines, and I believe will arouse as 
much discussion as Weismann's hypothesis did ; 
and it is probable that it will have a wider influ- 



EVOLUTION OF PLANTS. 167 

ence. Whether it expresses the actual means of 
heredity or not it is yet much too early to say; but 
this hypothesis is a greater contribution to science 
than the so-called " Mendel law " as to the nu- 
merical results of hybridization : the hypothesis 
attempts to explain the "law." 1 

One great merit of the hypothesis is the fact 
that its basis is a morphological unit, or at least 
an appreciable unit, not a mere imaginary concept. 
This unit should be capable of direct study, at 
least in some of its phases. It would seem that 
the Mendelian hypothesis would give a new direc- 
tion to cytological research. 2 

It is yet too early to say how far Mendel's law 
applies. We shall need to re-study the work that 
has been done and to do new work along more 
definite lines. There are relatively few results 
of experiments that can be conformed to Mendel's 
law, because the data are not complete enough 
or not made from the proper point of view. We 
should expect the fundamental results to be 
masked when the plants with which we work are 
themselves unstable, when cross-fertilization is 
allowed to take place, or when the pairs of con- 

1 This, I take it, is also the opinion of Bateson, the leading 
interpreter of Mendel in English ; for he calls his new book on 
the subject (1902) " Mendel's Principles of Heredity," as if the 
heredity idea were greater than the hybridization idea. 

2 See, for example, "A Cytological Basis for the Mendelian 
Laws," Bull. Torr. Bot. Club, 29, 657 (1902), by W. A. Cannon. 



lt>8 RECENT OPINIONS. 

trusting characters are very numerous and very 
complex. Marked numerical results have been 
found by various workers in different fields, in 
this country notably by Spillman in hybrid wheats. 
Mendel was able to discover the numerical law 
because he eliminated nearly all the confusing 
contingencies. In the discussion of every bold 
new hypothesis, we are in danger of becoming 
partisans, taking a stand either for it or against it. 
The judicial attitude is also the scientific one. 
We want to know. 

Two processes are now going forward in the 
discussion of Mendel's law, — one the explaining 
away of " exceptions," the other the endeavoring 
to find the true place of the law in the scheme of 
evolution. The one is primarily an effort to up- 
hold the law ; the other is primarily a desire to 
adjudge it. One is an effort to apply it uni- 
versally ; the other to determine whether it is 
universal. Already so many adjustments have 
been made of the Mendelian principles that it is 
becoming difficult to determine what Mendelism 
is. These cases are typical of the discussions on 
almost every vital question connected with evolu- 
tion. At the hard places we make a supposition 
and modify the hypothesis in the face of a fact. 
We can prove anything by supposing. 

The results of Mendel's work have two impor- 
tant bearings on current evolution discussion : (1) 



EVOLUTION OF PLANTS. 169 

on the part that hybridization plays under natural 
conditions in the evolution of the forms of life, and 
(2) the part that it plays in plant-breeding. In 
the former category his work gives a hint of defi- 
niteness to the role of hybridization in the origi- 
nation of new combination-forms. In the latter 
category it is difficult as yet to measure its im- 
portance, since extended applications to practice 
have not been made, and since, also, the Mendelian 
principles have been themselves so much the sub- 
ject of debate and definition that it is difficult to 
distinguish between Mendelism and the endeavor 
to make the Mendelian suggestions fit our present- 
day knowledge. In discussing the application of 
Mendel's work to plant-breeding, I desire to keep 
in mind the work that he did with peas, upon which 
the " Mendel law " chiefly rests. 

c. Apj>licatio)i to Plant- Breeding. 

The wildest prophecies have been made in re- 
spect to the application of Mendel's law to the 
practice of plant-breeding, for the mathematical 
formulas express only definiteness and precision. 
Unfortunately, the formulas cannot express the 
indefiniteness and the unprecision which even 
Mendel found in his work. My own feeling is 
that the greatest benefit of Mendel's work to the 
plant-breeder will be in improving the methods of 



170 RECENT OPINIONS. 

experimenting. We can no longer be satisfied 
with mere "trials" in hybridizing: we must plan 
the work with great care, have definite ideals, 
" work to a line," and make accurate and statisti- 
cal studies of the separate marks or characters of 
plants. His work suggests what we are to look for. 
Beyond this I do not see how the original Men- 
delian results will greatly modify our plant-breed- 
ing practice. The best breeders now breed to 
unit characters, for this is the significance of such 
expressions as " avoid breeding for antagonistic 
characters," " breed for one thing at a time," 
"know what you want," "have a definite ideal," 
" keep the variety up to a standard." In certain 
classes of plants the Mendelian laws will be found 
to apply with great regularity, and in these we shall 
be able to know beforehand about what to expect. 
The number of cases in which the law or some 
modification of it applies, is being extended daily, 
both for animals and plants ; 2 but in practice we 
shall probably find as many exceptions to the for- 
mulas as confirmations of them, even though the 
exceptions can be explained, after we find them, by 
Mendel's principle of heredity. 

1 See, for example, Bateson and Saunders's report to the Royal 
Society on heredity. A recent paper by Cuenot (Archives of 
Exper. and Gen. Zool., 1903) gives confirmatory results on 
hybrid mice, with discussions of the nature of dominance. 
This line of investigation is likely to be very popular for the 
next few years. 



EVOLUTION OF PLANTS. 171 

It has been said that we shall soon be able, as a 
result of Mendel's discoveries, to predict varieties 
in plant-breeding. Before considering this ques- 
tion, we must recall the fact that a cultural variety 
is a succession of plants that has characters suffi- 
ciently marked and uniform to make it worth 
cultivating in place of some older variety. Now 
and then it may be worth while to introduce some 
new energy or new trend into a general lot of 
offspring by making wholesale crosses, not ex- 
pecting ever to segregate any particular variety 
or strain from the progeny ; but these cases are 
rare, and the gain is indefinite and temporary. 
So far as our knowledge at present goes, I see no 
warrant for the hope that we can predict varieties 
with any degree of exactness, at least not beyond 
a very narrow effort. Following are some of the 
reasons that seem to me to argue against the 
probability of useful prophecy of varieties so far 
as the Mendelian results are concerned : (1) We 
do not know what plants will Mendelize until 
we try. (2) Even in plants that do Mendelize, 
only half of the offspring have stable characters. 
But we cannot predict for even this half, for it is 
impossible to determine beforehand which seeds 
showing dominant characters (and these are three- 
fourths of the offspring) will " come true." Domi- 
nance, as we have seen, is of two kinds in respect 
to its behavior in the next generation, — constant 



172 RECENT OPINIONS. 

and hybrid ; and the hybrid dominance, which is 
twice as frequent as the other, breaks up into con- 
stant dominance, hybrid dominance, and recessive- 
ness. (3) Mendel's law deals primarily with mere 
characters, not with a variety or with a plant as a 
whole. Every plant is a composite of a multitude 
of characters, and from the plant-breeder's point of 
view there ma}' be as many undesirable characters 
as desirable ones. No plant is perfect ; if it were, 
there would be no need of plant-breeding. The 
breeder wants to preserve the desirable characters 
or traits and eliminate the undesirable ones ; but 
under the strict interpretation of Mendelism this 
may be difficult and perhaps impossible. The one 
germ gamete and the one sperm gamete that unite 
to make the new plant, each contain all the alter- 
native parental characters ; these various char- 
acters reappear in the offspring, and all that the 
breeder gains is a new combination or arrangement 
of characters, and the undesirable attributes may 
be as troublesome as before. (4) The breeder 
usually wants wholly new characters as well as re- 
combinations of old ones, or he wants augmented 
characters, and these lie outside the true Mende- 
lian categories. For example, a carnation grower 
wants a four-inch flower, but he has only three-inch 
flowers to work with, and augmentation of charac- 
ters is no part of the original Mendelian law. Per- 
haps these augmented and new characters are to 



EVOLUTION OF PLANTS. 173 

be got by means of ordinary variation and selec- 
tion, or other extra-crossing means ; but we know, 
as a matter of fact, that augmented characters do 
sometimes appear in hybrids. (5) New and un- 
predictable characters are likely to arise from the 
influence of environment or other causes, and very 
likely these may be recorded in the gametes and 
vitiate the final results. (6) Variability itself 
may be a unit character and therefore pass over. 
There is probably such a thing as a " tendency to 
vary," wholly aside from the fact of variation. 
(7) Many of the plants with which we need most 
to work in plant-breeding are themselves eminently 
variable and the results, even if there is true Men- 
delism, may be so uncertain as to be wholly unpre- 
dictable. (8) Many plants with which we must 
work will not close-fertilize. Some of them are 
monoecious or dioecious. Even if there is gametic 
purity in such plants, the probability is that the 
fact can be discovered only by a long line of scien- 
tific experimenting for that particular purpose and 
not by the work of the man who desires only to 
breed new plants. (9) A cultural variety, in any 
true acceptation of the term, is a series of closely 
related plants having a pedigree. It runs back 
to one individual plant, from which propagation 
has been made by seeds or asexual parts. Now, 
one can never predict just what combination of 
characters any plant will have, even though it be 



174 RECENT OPINIONS. 

strictly Mendelian. A person might have a thou- 
sand hybrids of which no one plant shows any two 
characters in the proportion of 3 to 1 (both seed- 
characters may appear in the same pod or in dif- 
ferent pods on the same plant), let alone all the 
characters as 3 to 1 or in other delinite relation ; 
and yet the total average numerical results might 
conform exactly to the Mendelian law. Mendel's 
law is a law of averages. The very fact that one 
must employ such large numbers to secure the 
numerical results shows that we cannot predict as 
to individuals. For example, in ten plants of pea, 
Mendel found the following ratios in respect to 
seed-shape and seed-color: — 

Shape. Color. Shape. Color. 



3.75 


1 


2.27 


1 


4.33 


1 


3.33 


1 


3.37 


:1 


4.57 


1 


3.66 


:1 


2.43 


1 


3.43 


:1 


2.80 


:1 


2.20 


1 


4.88 


1 


1.90 


1 


2.59 


:1 


4.66 


:1 


3.57 


1 


2.91 


1 


1.85 


1 


3.57 


:1 


2.44 


1 



Mendel reports one instance in which the ratio in 
seed-shape was 21 to 1, and another of 1 to 1. He 
also reports instances of seed-color of 32 to 1, and 
1 to 1. It has been said that, because of Mendel's 
work, we shall be able to produce hybrid varieties 
with the same certainty that we produce chemical 
compounds. Now, a plant is made up of many 
combinations of many units, and these combina- 
tions are the results of mathematical chance or 
probability. Of course, when the offspring are 



EVOLUTION OF PLANTS. 175 

numerous, all possible combinations are likely to 
occur ; but these occurrences are essentially for- 
tuitous. Chemical compounds are specific entities 
in which the parts combine by necessity with defi- 
niteness. The comparison, as it appeals to me, is 
fallacious and the conclusion unsound. 

We must remember that there are whole classes 
of cases of plant-breeding that do not fall under 
hybridization at all. Granting the De Vriesian 
view that selection is incompetent to produce 
species from individual fluctuations, it is never- 
theless well established (and admitted by De Vries) 
that very many of our most useful cultural varie- 
ties have been brought to their present state of 
perfection by means of selection ; and by selection 
they are maintained in their usefulness. Selection 
will always be a most important agency in the 
hands of the gardener and the plant-breeder — 
none the less so now that we have challenged its 
role in the evolution of the plant kingdom. For 
the time being, the new discussions of hybridiza- 
tion are likely to overshadow all other agencies in 
plant-breeding ; but selection under cultivation is 
as important now as it was in the days of Van 
Mons and Darwin. 

d. Interpretation of Hybridism. 

It is probable that the clearest insight into 
this whole new question of hybridization is to be 



176 RECENT OPINIONS. 

got by following the work of De Vries. The 
concluding parts of the second volume of his 
" Mutationstheorie," a volume devoted wholly to 
hybridization, is on the press at this moment. 
The Mendelian laws are fully discussed in this 
volume, but the summary conclusions may be pre- 
sented here. De Vries had been working at 
hybridization long before he discovered Mendel, 
and had arrived at practically the same results ; 
he had also arrived at other results that are not 
Mendelian. De Vries denominated the law of 
numerical segregation as the " law of separation 
of characters in crosses." Like Mendel, he had 
found that merely to cross "varieties" or "species" 
is of no avail in the study of fundamental prob- 
lems ; for the varieties and species that we know 
are mere systematic groups with characters of 
all kinds and degrees. We must cross characters 
or units, not species. 

Every unit-character De Vries conceives to be 
represented in the germ by a pangene. This pan- 
gene may be active, in which case the character 
appears in the plant ; or it may be dormant, in 
which case the character is not visible, or for the 
time being is lost. Active pangenes may at any 
time become latent, or latent ones may become 
active. 

Mendel's law results from an interchange of 
contrasting characters. True physiological or 



EVOLUTION OF PLANTS. 177 

elementary species differ from each other by new 
unit-characters. They have arisen by progressive 
mutation. The characters are not contrasting or 
differentiating. One species has one kind of pan- 
gene, another species another kind of pangene. 
On combining these there can be no interchange 
of characters, and, therefore, no Mendelism. There 
is nothing for one character to exchange against 
the other. In the case of true progressive muta- 
tions, therefore, upon which the progress of the 
plant race depends, there can be no Mendelizing. 
Hybrids in these cases are intermediates, or else 
follow only one or the other of the parents. 

Now, varieties differ from true mutative species 
in the fact that they have contrasting characters. 
These characters are represented by their special 
kinds of pangenes. The pangene may be active 
or passive. That is, the variety may be a variety 
because one or more of its characters has become 
latent (retrogressive), or because characters have 
become active (degressive). When these charac- 
ters are crossed, there is an interchange of the 
pairs. Both parents bear the same unit-character, 
but this character is active in the one and dormant 
in the other. The hybrid receives an active pan- 
gene from one parent and a similar but inactive 
pangene from the other. When these two units 
unite, the calculus of chance determines that there 
shall reappear in the second generation equal num- 



178 RECENT OPINIONS. 

bers of both the parental units, and a half of the 
whole that are still hybrids and break up in the 
same ratio in the third generation. That is, true 
Mendelism is confined to crossings of retrogressive 
and degressive varietal characters. 

There are, therefore, two general classes of hy- 
brid formation: the isogons, giving rise to crosses 
in which two antagonistic parental characters 
reappear in numerical order (Mendelian cases); 
anisogons, giving rise to crosses in which two 
antagonistic characters sometimes separate un- 
equally, but ordinarily do not separate at all. 
When only one parent is represented in the off- 
spring, we have the "unisexual crosses" of Macfar- 
lane or the " false crosses " of Millardet. These 
are cases in which there are no true contrasting 
characters. Spillman has recently explained the 
false hybrids by supposing that the plants in this 
case are self -fertile and sterile with other pollen. 
That is, A is fertile with A, B with B, but A is 
not fertile witli B nor B with A ; there results, 
therefore, no true crossing. This hypothesis 
should be capable of experimental proof or dis- 
proof. 

The isogon hybrids are of all degrees of com- 
plexity, and classification of them will at once 
show how far we have already got away from the 
old systematic idea of variety-hybrids and species- 
hybrids. Hybrids between plants that differ only 



EVOLUTION OF PLANTS. 179 

in one unit-character are monohybrids. These are 
the ones in which the numerical results are most 
clearly traced, but they are also exceedingly rare. 
Those in which two unit-characters are concerned 
are dihybrids. In these the combination series 
gives four different kinds of offspring. So there 
are trihybrids, giving eight possible combinations, 
tetrahybrids, and so on to polyhybrids ; and in 
every succeeding grade the difficulties of statistical 
and comparative studies increase. Of how many 
characters is a plant composed ? 

e. Conclusion. 

Now, in conclusion, what are the great things 
that we have learned from these newer studies ? 
(1) In the first place, we have been brought to a 
full stop in respect to our ways of thinking on 
these evolution subjects. (2) We are compelled 
to give up forever the taxonomic idea of species 
as a basis for studying the process of evolution. 

(3) The experimental method has finally been 
completely launched and set under way. Labora- 
tory methods, comparative morphology, embryo- 
logical recapitulation, life-history studies, ecological 
investigations — all these means are likely to be 
overshadowed for a time by experiments in actu- 
ally growing the things under conditions of control. 

(4) We must study great numbers of individuals 



EVOLUTION OF PLANTS. 181 

and employ statistical methods of comparison. 
(5) The doctrine of discontinuous evolution is 
now clearly before us. (6) We are beginning to 
find a pathway through the bewildering maze of 
hybridization. 

Mendelism in Wheat. 

In order that I may present a specific example 
of evident Mendelian results, I have asked W. 
J. Spillman, agriculturist of the Department of 
Agriculture, to explain some of his experiments 
with wheat. 1 Mr. Spillman independently dis- 
covered numerical results, before the knowledge 
of the Mendelian experiments had become gen- 
erally known. 

" The photograph (p. 183) shows three genera- 
tions of one of my hybrid wheats. Of the three 
heads in the upper row, the left-hand one is the 
male parent (variety Valley); the right-hand one 
is the female parent (variety Little Club) ; and the 
middle one is the hybrid. The second row shows 
the second generation, and the third row the third 
generation.* Of the six types in the second gener- 
ation, the following points are important : Each 
type was present in a certain proportion, which 
was approximately the same as in thirteen other 
similar cases, and the average of these fourteen 
cases closely approximated the theoretical numbers 
1 For illustration in maize, see p. 227. 



182 



RECENT OPINIONS. 



called for by Mendel's hypothesis of the disjunc- 
tion of parental characters. The three at the left, 
being bearded, possess a character which was latent 
in the first generation. The fact that the beards 
show in these three indicates that the opposite char- 
acter is absent, and they should therefore remain 
bearded in succeeding generations. That is, they 
are no longer hybrid with reference to this charac- 
ter. It will be observed that this was actually the 
case, for no beardless heads appeared in the progeny 
of either of these three (see lower row, first five 
heads). The following diagram will show the char- 
acter of each of the six types in row two. In this 
diagram the letters have the following meanings: — 

B — bearded (written b when latent). 
S = smooth (not bearded). 
L — long heads. 
C = club heads (short) . 

J = intermediate in length of head. (The hybrid was interme- 
diate in this respect.) 

Parents. 



BL 



SG 



First Generation. 


Second Generation 




\BL 




2BI 




1BC 




2 SbL 


Sbl 


4 Sbl 

2 SbC 




1 SL 




2 SI 




1 sc 


16 




Three Generations of Hybrid "Wheat. 



A 1 = male parent, A 2 = the hybrid, A 3 = female parent. B 1-6 = the progeny 
of A 2. C 1 = progeny of B 1 . C 2-4 = progeny of B 2. C 5 = progeny of B 3. C 6 
and 7 = progeny of B 4. C 8-13 = progeny of B 5. C 14 and 15 = progeny of B 6. 
The results in the fourth generation, available too late to include in the photograph, 
indicate that B 2 and B 3, while not always separable on external appearances, are 
absolutely different, the one being hybrid, the other pure. 



184 RECENT OPINIONS. 

"This diagram shows the nine types called for 
by Mendel's theory. Of these, BL, BC, SL, and 
SC are no longer hybrids — at least they have no 
latent characters, and will therefore reproduce true 
to seed. Of the remaining five types, BI und SI 
are hybrid only with reference to length of head, 
and SbL and SbC only with reference to beards; 
while Sbl is hybrid with reference to both char- 
acters, as in the preceding generation. 

" It will readily be seen that the types BL and 
BC can be separated from the other seven by ex- 
ternal appearances, and obtained in a pure state. 
BL is the type shown at the left in the second 
row in the picture, and all its progeny was like it, 
showing that it conformed to theory. BC is the 
type shown at No. 3 in the second row of heads ; 
being pure, it should reproduce itself true to type, 
which it did, with an easily explained exception to 
be noted below. The type BI (shown at No. 2, 
row 2) being hybrid with reference to length of 
head, should produce again all the types based on 
this character, and it did this as is seen in heads 
2-4, row 3. Referring again to the above diagram, 
it will be seen that the types SL and SbL cannot 
be distinguished by external characters. SL will 
of course reproduce true to type, while SbL will 
produce SL, SbL, and BL. Now SL and SbL 
being mixed together in the selection made in the 
second generation, we should find a large percent- 



EVOLUTION OF PLANTS. 185 

age of SL mixed with some SbL from which it 
cannot be distinguished, and a small percentage of 
BL in the third generation. Heads 6 and 7, row 3, 
show that the types called for actually occurred. 
Types SI 2l\\(\. Sbl of the diagram appear alike ex- 
ternally, and were therefore selected together in the 
second generation (see head 5, row 2). Now SI 
should produce the types SL, SI, and SO, while Sbl 
should produce all nine types again (these nine 
types can be separated only into six by external 
appearance). It is therefore seen that the group 
represented by head 5, row 2, should produce all 
six types again. Heads 8-13, row 3, show these 
types. Types SbO said SOoi the diagram are alike 
externally, and were hence selected together last 
year. Of these SO should produce only SO, while 
SbO should produce SO, SbO, and BO. But 
since SO and SbO look alike, the progeny of 
these two types should show only SO and BO. 
The last two heads in row 3 show that this 
actually occurred. 

"In the single set of heads shown, there were 
two easily explained exceptions to theory. It will 
be seen that heads 2 and 3, row 2, differ only in 
length ; now the group represented by head 2 
varied in length from that of 1 to that of 3. In 
separating 2 and 3, it might easily happen that 
some of 3 should be placed with two. In this case 
the progeny of 3 would show a few heads like 1, 



186 RECENT OPINIONS. 

and this was the case. I have shown in the photo- 
graph only the heads called for by theory, for it 
would only lead to confusion to include the excep- 
tions which would probably not have occurred if 2 
and 3 of row 2 had been accurately separated last 
year. Again, in the progeny of the group repre- 
sented by head 5, row 2, only five of the six types 
shown (row 3, heads 8-13) were found in this par- 
ticular case, though all six were found in most of 
the others. As the missing type should constitute 
only 41 per cent of the group, and as it differed 
from one of the others only slightly, it is possible 
that it was included with the related type when 
the selections were made. 

" I have not yet seen the data for the third gen- 
eration of all these wheats, but those which are 
at hand are decidedly interesting. 1 The following 
are the data for the third generation of the cross 
between Jones Winter Fife (male) and Little 
Club (female). The Fife is long-headed, and has 
velvet chaff ( V) ; the Club short-headed, and has 
glabrous chaff ( (7) . Velvet proved to be dominant 
over glabrous, and the hybrids were intermediate in 
length. Type I. of the second generation included 
the two types VL and VgL, since these could not 
be distinguished by external appearances. Seed 
of Type I. produced in the third generation : — 

1 Data for the fourth generation, now at hand, agree well 
with the theory. 



EVOLUTION OF PLANTS. 187 

Plot. Percentage of Types. 

I. = VL. II. = GL. 

1 87 13 

2 81 19 

Theory 83$ 16| 

The figures for the remaining five second-genera 
tion types are as follows : — 







Type 


II. = 


GL. 












Percentage o 


f Types. 






Plot. 






II. 








1 






100 








2 






100 








Theory 






100 








Type III. 


= VI and VgL 






Plot. 


I. 


II. 


in. 


IV. 


V. 


VI. 


1 


21 


7 


38 


9 


20 


5 


2 


19 


4| 


38 


12 


15 


4 1 
2JL 


eor 
3 lot, 


V 20f 


Type 
II. 


411 
IV. 


8i 
= GI. 

IV. 


20| 


4! 

VI. 


1 




28 




52 




20 


2 




31 




47 




22 


leor 


y 


25 




50 




25 



Type V.= VCan&VgC. 



Plot. 

1 

:2 

Theory 





I. II. 




v. 


VI. 




2.4 




80.0 


17.6 




4.7 2.6 




79.8 


12.9 


Y 






831 


16| 




Type VI. = 


--GO 






Plot. 


ii. 






VI. 


1 


7.7 






92.3 


2 








100.0 



Theory 100. 



188 RECENT OPINIONS. 

" The only departures from theory of any conse- 
quence in these data are the occurrence of small 
amounts of Types I. and II. in the progeny of V., 
and of II. in the progeny of VI. Now, Type V. of 
the second generation (VO and VgC) differed from 
Type III. (VI) only in being slightly shorter. 
If a feAV individuals of III. had been included in 
V. in separating the types of the second generation, 
we should have the actual result obtained in the 
third generation. Likewise, Type VI. of the sec- 
ond generation (GrO) differed from II. (GrI) in 
the same manner. Evidently a few plants of II. 
got into the Type VI. last year, and thus gave the 
results shown. 

" These hybrids are now under the care of Pro- 
fessor E. E. Elliott, of Pullman, Washington ; and 
from a recent letter I infer that spring character 
in wheats is dominant over the winter character, as 
a large majority of the fourth generation have the 
spring character (all the club wheats used were 
spring wheats). 

" The original purpose of this work was to pro- 
duce a winter-club wheat, a type much needed in 
eastern Washington. It is probable that the effort 
was successful, but the invariable interruptions to 
work that follow a change of personnel in the 
workers has delayed the final results. 

" It now seems probable that Mendel's theory 
is true, at least in these wheats. If this theory 



ON HYBRIDIZATION. 189 

should prove generally true, the following most 
important fact follows : If the individuals of the 
second generation are numerous enough, there is 
present in this generation every possible combina- 
tion of the parent characters, and, most important 
of all, every one of these combinations is present 
in some individuals in a fixed form that will re- 
produce true to seed. The fixed forms can easily 
be separated from the others by treating each 
plant of the second generation as an individual, and 
noting which of them reproduce true to seed. 

" It should further be noted that the forms not 
already fixed in the second year will, in later gen- 
erations, gradually break up into the same fixed 
forms as those occurring in the second generation. 
It is therefore possible to secure in the third gen- 
eration all the pure fixed forms that can be secured 
from a hybrid. (Close fertilization is assumed in 
all cases.)" 

II. On Hybridization. 

By Hugo De Vries. 

(Written expressly for the third edition of " Plant-Breeding.") 

Hybrids are ordinarily said to be intermediate 
between their parents. But by a closer inspection 
this relation appears to be of a complex nature ; 
for the intermediate state may be such in regard 



190 RECENT OPINIONS. 

to the single characters, or may be the result of 
the mixing of pure or nearly pure paternal and 
maternal characters in the same individual. Gen- 
erally it is said that specific characters are handed 
over in a more or less reduced degree, but that 
racial peculiarities take either to the father or to 
the mother. 

The difference between specific and racial marks 
is of course as much a question of personal appre- 
ciation as is the limit between species and races or 
varieties itself. But it is clear that the behavior 
of hybrids, both natural and artificial, does not 
depend upon our appreciation of the facts, but on 
the facts themselves. We have therefore to search 
for a character which is independent of the syste- 
matic value given to the groups in question. 

Such a criterion is yielded by the theory of the 
origin of species by mutations. Of course the 
theory only indicates the principle, and much 
work will have to be done before it will be pos- 
sible to apply it in all individual cases. But a 
clear conception of the ruling idea will point to 
the direction in which the experiments will have 
to be made, and it will assist the hybridist in a 
more thorough comparison of the hybrids and 
their parents. Moreover, a consideration of the 
characters of the parents from the new point of 
view will enable him, in the majority of cases, to 
foretell, with a greater or lesser degree of preci 



ON HYBRIDIZATION. 191 

sion, the characters which may be expected to 
make their appearance in a new hybrid. 

The theory of mutation assumes that the quali- 
ties of a plant are not the expressions of a single, 
so-called " specific character," but depend on dif- 
ferent units. These units are more or less inde- 
pendent of one another, and may be combined in 
different ways. Two or more allied species might 
consist of absolutely the same characters, but in 
different combinations. 

According to this view the progress in living 
nature has been by steps. Each step contributes 
a new character to those already existing, adding 
one unit more to the stock. It is evident that of 
all the species of a genus, the nearest ally of any 
given one is that from which it has taken its 
origin. This origin is assumed to have taken 
place by shocks or leaps ; or if the idea of a leap 
should confer the notion of too great a difference, 
one might use the expression, "by steps." In 
horticulture such steps are often called sports ; but 
the meaning of this word comprises so many notions, 
and is so often limited to bud-sports, which mostly 
are of another nature, that I prefer to avoid it. 

Each leap or step signifies the acquisition of 
a single new character ; and elementary species 
must therefore differ from their nearest allies 
only in the possession of a single one. As a mat- 
ter of fact, the difference between the species of 



192 RECENT OPINIONS. 

one genus are often not only greater, but even 
very much greater. But this is accounted for by 
the extinction of a greater or lesser number of 
forms, which no doubt is and has been of very 
general occurrence and must of course break up 
the continuity in the series of the remaining types. 
In such groups as Draba vema, Helianthemum vul- 
gare, Viola tricolor, the hieraciums, roses, bram- 
bles, and many other so-called younger genera and 
species, the single forms are so nearly allied that 
it is very difficult or perhaps even impossible to 
distinguish them from one another. These are 
the types of the original arrangement which is to 
be assumed for all groups consisting at present 
of more widely different forms, and, as is com- 
monly said, now showing "gaps." 

Such small steps are called mutations, and more 
particularly progressive mutations, because they 
contribute to the evolution of the group. Once 
obtained, a new character may remain constant 
for centuries, and the new species will show no 
progress till a further mutation takes place and 
changes it again into a new specific form. The 
whole evolution goes on by such steps, the peri- 
ods between the successive bounds showing no 
signs of progress, but leaving the species un- 
changed. In this way it is clear that constancy 
of species and mutual descendance are in perfect 
harmony with one another. 



ON HYBRIDIZATION. 193 

Besides the progressive mutations, there are 
other changes which are of minor value for the 
evolution in general, but of more general interest 
to horticulture. First of all, a character, once 
obtained, may be visible in the plant or it may 
become invisible, inactive, or as it is ordinarily 
called, dormant or latent. For instance, the blue 
and red colors of many flowers may disappear and 
thereby give rise to the white-flowered varieties. 
The visible quality is lost in such cases, but the 
corresponding internal one is not really lost, but 
has only become inactive or sleeping. That this 
is the case is seen in the frequent reversions in 
general, and particularly in the numerous instances 
of reversion by bud- variation as shown by varie- 
gated trees and shrubs, and by quite a host of 
garden varieties of evergreens (e.g. Cephalotaxus 
pedunculata var. fastigiata, Cryptomeria Japonica 
var. spiraliter falcata, etc.). 

If now we compare a species with its mother- 
species, and a variety with its species, we readily 
see the difference. In both cases the difference in 
the description is caused by but a single character. 
But in the first case the internal character of the 
germ is present in the one and wanting in the 
other, whilst in the second case it is present in 
both and only different as to the degree of its 
activity, being active in the one and latent in the 
other. 



194 RECENT OPINIONS. 

From this comparison we at once see that the 
behavior of two plants, when sexually united with 
one another, must differ principally in the two 
instances above mentioned. All other characters 
are assumed to be the same in both parents, and 
their union must follow the common rule of fer- 
tilization. But we must expect to get a different 
hybrid if the diagnostic character present in the 
elder one of the two forms is wanting in the 
younger one or is present but inactive. The 
active and the latent character may be simply in- 
terchanged, but in the case of a progressive mu- 
tation an exchange of characters is of course 
impossible. 

Activity and latency are not the sole degrees of 
development of a character. Nor is the difference 
between two forms, used for a crossing, ordinarily 
limited to a single point. But for the sake of 
clearness it seems better first to discuss these more 
simple cases and to put off the more complicated 
ones till after having elucidated the former. 

The becoming dormant of a character is one of 
the most ordinary types of the production of varie- 
ties. It is to be regarded as a mutation, since it 
is known in horticulture to come about by leaps 
and bounds. In the outer features it sets back 
the evolution as much as it had been brought for- 
ward by the progressive mutation by which the 
character in question was first obtained. For 



ON HYBRIDIZATION. 195 

this reason the seeming loss may be called a retro- 
gressive mutation. 

Limiting ourselves provisionally to these two 
types of differences between the two plants chosen 
for a crossing experiment, we will, for brevity's 
sake, call " species " two forms of which the one 
has been derived from the other by a progressive 
mutation, and " variety," the form derived from 
another in the way of retrogressive mutation. In 
this way we come to a very simple statement of 
the internal phenomena of crosses in general. 
For, in the first case, one parent has a character 
which is lacking in the other, and no exchange is 
possible. In the second case, both parents bear 
the same character, active in one, dormant in the 
other, and here they may therefore simply be ex- 
changed. 

This exchange is governed by the laws of proba- 
bility and depends, as far as we know, on no other 
principle or general laws. The application of the 
laws of probability to this process was first dis- 
covered by Mendel, and the laws of exchange of 
characters in hybrids are now generally known as 
the laws of Mendel. They are limited to the 
crossing of varieties. 

If no exchange is possible because the differ- 
ential character is wholly wanting in the other 
parent, we may call the union "unisexual," as was 
first proposed by Macfarlane. The extant features 



196 RECENT OPINIONS. 

are then handed clown to the hybrid offspring, but 
in a reduced state. Ordinarily they are reduced 
to one-half, as Macfarlane has pointed out ; but this 
is only a mean, around which the single cases seem 
to be grouped in the ordinary manner, most of 
them more or less strictly observing the rule, 
others differing in varying degrees. In extreme 
cases such variation can go so far as to repeat the 
character in question in the hybrid, or, on the other 
hand, to cause it to be wholly wanting. Hybrids 
from such unisexual crosses are ordinarily constant 
in their progeny, repeating in each successive gener- 
ation the characters of the first one. Such races do 
not obviously differ from true species, and Kerner 
has shown that in many cases wild species may 
owe their origin to such a cross. But instances 
are as yet rare, because, ordinarily, the two plants 
chosen for a cross differ in more than one point, 
and even mostly differ partly in specific characters, 
and partly in such as have been obtained by retro- 
gressive mutations. 

Hybrids of varieties follow Mendel's laws, as 
we have said. Two essential points are here to 
be distinguished, viz., the character invisible in 
the hybrid itself, and the behavior of the two 
opposite qualities in their progeny. We will first 
consider the hybrids themselves. 

According to the limits chosen above for our 
present discussion, the hybrid inherits from one 



ON HYBRIDIZATION. 197 

parent a character in an active condition, and from 
the other the same character in a dormant state. 
From this method of viewing their constitution, 
it is evidently to be expected that the differential 
character will be active in the hybrid too, perhaps 
aided but perhaps also more or less hindered in its 
expression by the dormant counterpart. The evi- 
dence afforded by the experiments of Mendel, 
Correns, Tschermak, Webber, and myself shows 
that the differential character is really active in 
the hybrids, and that the weakening by its dormant 
opponent is ordinarily very slight, often wholly 
wanting, and only occasionally reducing it to nearly 
one-half. (Hyoscyamus pallidus x niger.*) This 
rule is commonly expressed by saying that the 
phylogenetically older character, i.e. that of the 
species, is dominant or prevailing over the antago- 
nistic character of the younger parent or the va- 
riety. It is the first of Mendel's laws, but here 
expressed in terms, not of Mendel, but proper to 
the mutation theory. 

The second of Mendel's laws governs the split- 
ting up of the character in the offspring of the 
hybrids. Mendel assumes that at the time of the 
production of the sexual cells the two antagonistic 
qualities, combined in the hybrid, separate and 
leave each other, the dominant coming into one- 
half of the male and female elements, and the 
opposite or recessive coming into the other half. 



198 RECENT OPINIONS. 

If now, in the act of fertilization, the male and 
female cells are combined simply according to the 
laws of probability, each cell has an equal chance 
to unite with a cell bearing the same or with a 
cell bearing the opposite character. This leads 
to four combinations of equal frequency, a male 
dominant combining with a dominant or a reces- 
sive female, and a male recessive uniting in the 
same way with a dominant or a recessive female. 
Or, having no regard to the sex, we have dominant 
x dominant, recessive x recessive, and two cases 
of dominant x recessive. 

The offspring of hybrids consists, therefore, of 
three different groups of individuals. One of them 
bears only the active character, one of them only 
the latent, and the other group, containing the 
double number of specimens of each of the two 
first, consists of new hybrids. The first group will 
have the character of one grandparent, the second 
that of the other, the third that of the parents or 
hybrids of the first generation. The two first 
divisions will be constant like the original parent- 
species ; the last one must split up in the same 
way as the original hybrids themselves. No new 
form is obtained by such a crossing, as no new com- 
bination of qualities was possible. The hybrids 
obtained are called monohybrids, because the 
parents differ only in a single point. They are 
evidently of no practical interest, but it is equally 



ON HYBRIDIZATION. 199 

evident that they give us the key to the explana- 
tion of the phenomena exhibited in the more com- 
plex cases ; for, as a rule, these obey the same laws 
as the monohjrbrids with respect to the different 
distinguishing characters, whilst these are them- 
selves combined according to the ordinary laws of 
probability. 

If we sexually combine two forms, which differ 
in two points, the hybrids are called dihybrids ; if 
the difference extends to three or more characters, 
they bear the names of tripolyhybrids. The most 
important result of the study of such cases is, that 
the different characters of the parents may be 
united by crossing and give rise to hybrids, of 
which some are constant in their progeny and 
others not. The last ones split up according to 
the same rules as do the monohybrids, and are only 
of theoretical interest or at best are the means of 
obtaining the constant races in an easier, though 
slower, way than by getting them directly. On the 
other hand, the constant races are of the highest 
value, as well in horticultural as in agricultural 
practice. As many combinations as are to be ex- 
pected really appear as constant races. If the 
crossed varieties differ in two characters, two 
new combinations are possible and obtained. For 
instance, by crossing the blue and thorny thorn- 
apple with the white-flowered thornless variety, 
one obtains blue thornless and white thorny forms, 



200 RECENT OPINIONS. 

each of which gives a constant race. In the case 
of three differential characters, eight combinations 
are possible, two of them are equal to the parents, 
and so we will expect six new races, as, for instance, 
in the cases of wheat and oats studied by Rimpau 
(cf. " Mutationstheorie," II., p. 192). The prac- 
tical horticulturists and agriculturists will have 
to choose from these new races the best ones for 
further cultivation, but the numerical laws of 
Mendel will enable them to calculate beforehand 
what they have to expect and in which way they 
have to direct their selections. 

The laws of Mendel are not only valid for the 
cases of retrogressive variations, they also may be 
applied to all other cases, in which the differential 
character is internally present in both parents 
of a cross, but in different conditions. The prin- 
cipal conditions are the active and the dormant 
ones, constituting, as we have seen, the species 
and the constant variety. But there are other 
conditions of which we have here to name only 
the semi-active one. This is the internal charac- 
ter of those extremely variable forms which are so 
highly esteemed in horticulture, as double flowers, 
variegated leaves, and so on. Crossed with the true 
species, they comply with Mendel's laws, and the 
results of the crossings, therefore, may be calculated 
beforehand. But their high degree of variability is 
inherited by the hybrids and makes it often very 



OX HYBRIDIZATION. 201 

difficult as well to prove this compliance as to make 
use of it in practice. 

Coming now to even more complicated cases, we 
have to treat of those in which some characters 
differ progressively or unisexually and others in 
the retrogressive or in the digressive way. Or, 
in other terms, we have to inquire into the cross- 
ings in which the parents differ at once in specific 
and in varietal or racial marks. It will be readily 
seen that this case, though very complicated from 
an analytical point of view, is in practice the ordi- 
nary one. Pure unisexual or pure Mendel crosses 
are very rare, and seldom of great importance. 
Nearly all interesting horticultural crossings bear 
the mixed character we now have to speak of. 
The mutation-theory of course assumes the recip- 
rocal independence of the single characters for 
this case also. The unisexual differences must 
follow the laws studied by Macfarlane, the antago- 
nistic qualities those pointed out by Mendel. In 
regard to the first, the hybrids will therefore be 
in some degree intermediate between the parents, 
and constant in their progeny. In regard to the 
last, they will bear the dominant characters, and 
split up in their children, giving as many new 
constant strains as new combinations of these 
characters are possible. 

It is evident that the applications of the laws 
above mentioned mav in this manner lead to the 



202 RECENT OPINIONS. 

calculating beforehand of the results of all pro- 
jected crosses. But the researches are as yet only 
in their prime, and the true distinction of the 
units of the characters, which has to be the base 
of all such calculations, demands much previous 
experimental work. 

The discussions given above concern only spe- 
cies and varieties in the ordinary immutable 
state. When mutable, the conditions of the in- 
ternal characters are of course totally different, 
and neither the laws of the unisexual crossings 
nor those of Mendel are applicable. (See De 
Vries's paper "On Crosses with Dissimilar 
Heredity.") 

III. The Forward Movement in Plant- 
Breeding. 1 

The first specific interest in cultivated plants 
was in the gross kinds or species. As the con- 
tact with plants became more intimate, various in- 
definite form-groups were recognized within the 
limits of the species. Gradually, with the intensi- 
fying of domestication and cultivation, very par- 
ticular groups appeared and were recognized. 
These smaller groups came finally to be designated 

1 Read April 2, 1903, before the American Philosophical 
Society, and reprinted, with minor alterations, from proceed- 
ings of the society, Vol. XLII. No. 172. 



THE FORWARD MOVEMENT. 203 

by names, and the idea of the definite and homo- 
geneous cultural variety came into existence. 
The variety-conception is really a late one in the 
development of the human race. It is practically 
only within the past two centuries that cultivated 
varieties of plants have been recognized as be- 
ing worthy of receiving designative names. It is 
within this period, also, that most of the great 
breeds of animals have been defined and separately 
named. 

All this measures the increasing intimacy of 
our contact with domesticated plants and animals. 
It is a record of our progress. The peoples that 
are most advanced in the cultivation of any plant 
are the ones that have the most named varieties 
of that plant. In Japan, to this day, the plums 
are said to pass under ill-defined class names. We 
have introduced these classes, have sorted out the 
particular forms that promise to be of value to us, 
and have given them specific American names. 
Not long ago a native professor in Japan wrote 
me asking for cions of these plums, in order that 
he might introduce Japanese plums into Japan. 
The Russian apples are designated to some extent 
by class-names ; in fact, it was not until the ap- 
pearance of Regel's work, about a generation ago, 
that Russian pomology may be said to have been 
born. What constitutes a variety is increasingly 
more difficult to define, because we are constantly 



204 RECENT OPINIONS. 

differentiating on smaller points. The growth of 
the variety-conception is really the growth of the 
power of analysis. 

The earlier recognized varieties seem to have 
come into existence unchallenged. There is very 
little record of inquiry as to how or why or even 
where they originated. That is, the quest of the 
origin arose long after the recognition of the va- 
riety as a variety. Even after inquisitive search 
into origins had begun there was little effort to 
produce these varieties. The describing of va- 
rieties and the search into their histories was a 
special work of the nineteenth century. One has 
only to consult such American works as Downing's 
"Fruits and Fruit Trees of America," and Burr's 
" Field and Garden Vegetables of America," to see 
how carefully and methodically the descriptions 
and synonymy of the varieties were worked out. 
These are types of excellent pieces of editorial and 
formal systematic work. 

There have been isolated efforts at producing 
varieties for many years. These efforts began be- 
fore the time of the general discussion of organic 
evolution. In fact, it was on such experiments 
that Darwin drew heavily in some of his most im- 
portant writing. Roughly speaking, however, the 
conception that the kinds of plants can be definitely 
modified and varied by man is a product of the last 
half century. We now believe that there is such 



THE FORWARD MOVEMENT. 205 

a possibility as plant-breeding. It is really a more 
modern conception, so far as its general acceptance 
is concerned, than animal-breeding. But both 
animal-breeding and plant-breeding are the results 
of a new attitude toward the forms of life — a con- 
viction that the very structure, habits, and attri- 
butes are amenable to change and control by man. 
This is really one of the great new attitudes of the 
modern world. 

Formerly, and even up to the present time, the 
variety has been taken as the unit for plant-breed- 
ing work, as it has been for descriptive and classi- 
ficatory work. Whether we believed it or not, Ave 
have accepted it as a fairly definite thing or entity. 
Yet, what is a variety? Only the ideal of one man 
or a set of men. Custom may define its boundaries, 
but in fact it has no boundaries. At best, a variety 
is only an assemblage of forms that agree rather 
more than they differ ; and any one of these forms 
may, with equal propriety, be called another va- 
riety. Shall we continue to consider the variety 
as a unit or basis from which we are to breed for 
the purpose of producing other varieties? Or shall 
we still further refine our ideals, and find that the 
variety-conception is really only a mark of an im- 
perfect and superficial expression of an immature 
age? 

Now, plant-breeding is worthy of the name only 
as it sets definite ideals and is able to attain them. 



206 RECENT OPINIONS. 

Merely to produce new things is of no merit : that 
was done long before man was evolved. A child 
can "produce" a new variety, but it may learn 
nothing and contribute nothing in producing it. 
I have myself produced fifteen hundred new kinds 
of pumpkins and squashes, but I had no idea 
what I was to produce, the world is no better 
for my having produced them, and I am no wiser 
(except in experience) than I was before. In 
many " new " things that are produced there may 
be dispute as to whether they are new, and as to 
whether they are distinct enough to be named and 
therefore to be ranked as varieties at all. This is 
not science, nor even breeding : it is playing and 
guessing. What does the world care whether 
John Jones produces "Jones's Giant Beardless 
Wheat " ? But it does care if he produces a wheat 
having a half of one per cent more protein. We 
must give up the production of mere "varieties" ; 
we must breed for certain definite attributes that 
will make the new generations of plants more 
efficient for certain purposes : this is the new out- 
look in plant-breeding. 

Happily, we are not without abundant accom- 
plishment in this new field. The last ten years 
has seen a remarkable specialization in the pro- 
ducing of plants that are adapted to particular 
needs. The days of merely crossing and sowing 
the seeds to see what will turn up are already past 



THE FORWARD MOVEMENT. 207 

with those who are engaged seriously in the work. 
The old method was hit-and-miss, and the result 
was to take what good luck put in our way : the 
new method proceeds definitely and directly, and 
the result is the necessary outcome of the line of 
effort. The crux of the new ideal is efficiency 
in one particular attribute in the product of the 
breeding. These attributes are measurable ; the 
kind of results are foreseen in the plan, or are 
predictable. 

All these remarks are typically illustrated in 
many investigations now making in the experi- 
ment stations. As an example, I will describe the 
experiments with corn-breeding now conducting 
in Illinois. It is significant to note what are the 
reasons for breeding new corns, as stated by Pro- 
fessor Hopkins in Bulletin 82 of the Illinois Ex- 
periment Station. 

" In its own publication a large commercial 
concern, which uses enormous quantities of corn, 
makes the following statements : — 

" ' A bushel of ordinary corn, weighing fifty-six 
pounds, contains about four and one-half pounds 
of germ, thirty-six pounds of dry starch, seven 
pounds of gluten, and five pounds of bran or hull, 
the balance in weight being made up of water, 
soluble matter, etc. The value of the germ lies in 
the fact that it contains over forty per cent of corn 
oil, worth, say, five cents per pound, while the 



208 RECENT OPINIONS. 

starch is worth one and one-half cents, the gluten 
one cent, and the hull about one-half cent per 
pound. 

" c It can readily be seen that a variety of corn 
containing, say, one pound more oil per bushel 
would be in large demand. 

" 4 Farmers throughout the country do well to 
communicate with their respective agricultural 
experiment stations and secure their cooperation 
along these lines.' 

" These are statements and suggestions which 
should, and do, attract the attention of experiment 
station men. They are made by the Glucose 
Sugar Refining Company of Chicago, a company 
which purchases and uses, in its six factories, 
about fifty million bushels of corn annually. Ac- 
cording to these statements, if the oil of corn 
could be increased one pound per bushel, the 
actual value of the corn for glucose factories 
would be increased five cents per bushel ; and the 
president of the Glucose Sugar Refining Company 
has personally assured the writer that his company 
would be glad to pay a higher price for high oil 
corn whenever it can be furnished in large quanti- 
ties. The increase of five cents per bushel on 
fifty million bushels would add $2,500,000 to the 
value of the corn purchased by this one company 
each year. The glucose factories are now extract- 
ing the oil from all the corn they use and are 



THE FORWARD MOVEMENT. 209 

unable to supply the market demand for corn oil. 
On the other hand, to these manufacturers protein 
is a cheap by-product, and consequently they want 
less protein in corn. 

" Corn with a lower oil content is desired as 
a feed for bacon hogs, especially for our export 
trade, very extensive and thorough investigations 
conducted in Germany and Canada having proved 
conclusively that ordinary corn contains too much 
oil for the production of the hard, firm bacon 
which is demanded in the markets of Great Britain 
and Continental Europe." 

It is very interesting to note that this does not 
mention the improvement of Learning's White, or 
Jones's Yellow Dent, or any other named variety 
of corn, nor does it propose that any new variety 
shall be created. It suggests what may be done 
with any variety of corn. The experiments in 
Illinois demonstrate that " the yield of corn can 
be increased, and the chemical composition of the 
kernel can be changed as may be desired, either 
to increase or decrease the protein, the oil, or the 
starch." 

The breeding of the corn, in the Illinois experi- 
ments, proceeds along two general lines, — for 
physical perfection and for chemical perfection. 
Selection for physical merit proceeds as follows, to 
quote again from Professor Hopkins : " The most 
perfect ears obtainable of the variety of corn 



210 RECENT OPINIONS. 

which it is desired to breed should be selected. 
These ears should conform to the desirable stand- 
ards of this variety, and should possess the prin- 
cipal properties which belong to perfect ears of 
corn, so far as they are known and as completely 
as it is possible to secure them. These physical 
characteristics and properties include the length, 
circumference, and shape of the ear and of the 
cob ; the number of rows of kernels and the num- 
ber of kernels in the row ; the weight and color of 
the grain and of the cob ; and the size and shape 
of the kernels. In making this selection the 
breeder may have in his mind a perfect ear of 
corn and make the physical selection of seed ears 
by simple inspection, or he may make absolute 
counts and measurements and reduce the physi- 
cal selection almost to an exact or mathematical 
basis." 

The selection for chemical content is made on two bases, 
— on the general gross structure of the corn kernel as 
determined by " mechanical examination," and on chemical 
analysis of the kernel. 

Chemical examination by means of mechanical examina- 
tion is as follows : " The selection of seed ears for improved 
chemical composition by mechanical examination of the 
kernels is not only of much assistance to the chemist in 
enabling him to reduce greatly the chemical work involved 
in seed-corn selection, but it is of the greatest practical 
value to the ordinary seed-corn grower who is trying to 
improve his seed corn with very limited service, if any, from 
the analytical chemist. This chemical selection of seed ears 



THE FORWARD MOVEMENT. 



211 



by mechanical examination, as well as by chemical analysis 
(which is described below), is based upon two facts : — 

" 1. That the ear of corn is approximately uniform 
throughout in the chemical composition of its kernels. 

" 2. That there is a wide variation in the chemical com- 
position of different ears, even of the same variety of corn. 
These two facts are well illustrated in the table : — 

Protein in Single Kernels. 





Ear A, 

Protein, 

Per 

Cent. 


EarB, 

Protein, 

Per 

Cent. 


EarC, 

Protein, 

Per 

Cent. 


EarD, 

Protein, 

Per 

Cent. 




12.46 


11.53 


7.45 


8.72 


Kernel No. 2 


12.54 


12.32 


7.54 


8.41 


Kernel No. 3 


12.44 


12.19 


7.69 


8.73 




12.50 


12.54 


7.47 


8.31 




12.30 


12.14 


7.74 


8.02 




12.49 


12.95 


8.70 


8.76 




12.50 


12.84 


8.46 


8.89 


Kernel No. 8 


12.14 





8.69 


9.02 


Kernel No. 9 


12.14 


12.04 


8.86 


8.96 


Kernel No. 10 


12.71 


12.75 


8.10 


8.89 



" It will be observed that while there are, of course, small 
differences among the different kernels of the same ear, yet 
each ear has an individuality as a whole, the difference in 
composition between different ears being much more marked 
than between different kernels of the same ear. 

" The uniformity of the individual ear makes it possible 
to estimate or to determine the composition of the corn 
by the examination or analysis of a few kernels. The re- 
mainder of the kernels on the ear may then be planted if 
desired. The wide variation in the composition between 



212 RECENT OPINIONS. 

different ears furnishes a starting-point for the selection of 
seed in any of the several different lines of desired improve- 
ment. 

" The method of making a chemical selection of ears 
of seed corn by a simple mechanical examination of the 
kernels is based upon the fact that the kernel of corn is 
not homogeneous in structure, but consists of several dis- 
tinct and readily observable parts of markedly different 
chemical composition. Aside from the hull which sur- 
rounds the kernel there are three principal parts in a grain 
of corn : — 

"1. The darker colored and rather hard and horny layer 
lying next to the hull, principally in the edges and toward 
the tip end of the kernel, where it is about three millimetres, 
or one-eighth of an inch in thickness. 

"2. The white, starchy-appearing part occupying the 
crown end of the kernel and usually also immediately sur- 
rounding, or partially surrounding, the germ. 

"3. The germ itself, which occupies the central part of 
the kernel toward the tip end. 

" These different parts of the corn kernel can be 
readily recognized by merely dissecting a single kernel with 
a pocket-knife, and it may be added that this is the only 
instrument needed by anybody in making a chemical selec- 
tion of seed corn by mechanical examination. 

" The horny layer, which usually constitutes about sixty- 
five per cent of the corn kernel, contains a large proportion 
of the total protein in the kernel. 

" The white, starchy part constitutes about twenty per 
cent of the whole kernel, and contains a small proportion of 
the total protein. The germ constitutes only about ten per 
cent of the corn kernel ; but while it is rich in protein, it 
also contains more than eighty-five per cent of the total oil 
content of the whole kernel, the remainder of the oil being 
distributed in all of the other parts. 



THE FORWARD MOVEMENT. 213 

" By keeping in mind that the horny layer is large in 
proportion, and also quite rich in protein, and that the 
germ, although rather small in proportion, is very rich in 
protein, so that these two parts contain a very large propor- 
tion of the total protein in the corn kernel, it will be readily 
seen that by selecting ears whose kernels contain more than 
the average proportion of germ and horny layer, we are 
really selecting ears which are above the average in their 
protein content. As a matter of fact, the method is even 
more simple than this, because the white, starchy part is 
approximately the complement of, and varies inversely as, 
the sum of the other constituents ; and to pick out seed corn 
of high protein content it is only necessary to select those 
ears whose kernels show a relatively small proportion of the 
white, starchy part surrounding the germ. 

" As more than eighty-five per cent of the oil in the 
kernel is contained in the germ, it follows that ears of corn 
are relatively high or low in their oil content, according as 
their kernels have a larger or smaller proportion of germ. 

" In selecting seed corn by chemical analysis, we remove 
from the individual ear two adjacent rows of kernels as a 
representative sample. This sample is ground and analyzed 
as completely as may be necessary to enable us to decide 
whether the ear is suitable for seed for the particular kind 
of corn which it is desired to breed. Dry matter is always 
determined in order to reduce all other determinations to 
the strictly uniform and comparable water-free basis. If, 
for example, we desire to change only the protein content, 
then protein is determined. If we are breeding to change 
both the protein and the oil, then determinations of both 
of these con tituents must be made." 

Any careful farmer can make such examinations 
as these. The relative abundance of one or the 



214 RECENT OPINIONS. 

other of three areas in the kernel will indicate 
what ears should be chosen for seed. Professor 
Hopkins proposes a system of field trials in which 
one ear furnishes plants for one row, thereby allow- 
ing the operator to see and measure the individu- 
ality of each ear. By choosing ears that most nearly 
approach the ideal, and then by continued selec- 
tion, the desired result is to be secured. 

It is impossible to overestimate the value of any 
concerted corn-breeding work of this general type. 
The grain alone of the corn crop is worth about 
one billion dollars annually. It is no doubt pos- 
sible greatly to increase this efficiency. 

An interesting cognate inquiry to this direct 
breeding work is the study of the commercial 
grades of grains. It is a most singular fact that 
the dealer's " grades " are of a very different kind 
from the farmer's "varieties." In the great mar- 
kets, for example, corn is sold as " No. 1 Yellow," 
"No. 2 Yellow," "No. 3 Yellow." Any yellow 
corn may be thrown into these grades. What 
constitutes a grade is essentially a judgment on 
the part of every dealer. There is, therefore, a 
very natural tendency on the part of dealers to 
deliver grain as near the bottom of the grade line 
as an inspector will pass, and consequently there 
is a marked deterioration as the grain reaches the 
seaboard. The result is that the grain is likely 
to be condemned or criticised when it reaches Liv- 



THE FORWARD MOVEMENT. 215 

erpool. Complaints having come to the govern- 
ment, the United States Department of Agriculture 
has undertaken to determine how far the grades of 
grain can be reduced to indisputable instrumental 
measurement. This work is now in the hands of 
C. S. Scofield, in the Bureau of Plant Industry. 
The result is likely to be a closer defining of what 
a grade is ; and this point once determined, the 
producer will make an effort to grow such grain as 
will grade to No. 1, and thereby reach the extra 
price. Eventually the efficiency points of the 
grower and the commercial grades of the dealer 
ought nearly or quite to coincide. There should 
come a time when corn is sold on its inherent 
merits, as, for example, on its starch content. This 
corn would not then be graded 1, 2, and 3 on its 
starch content, because that content would be as- 
sured in the entire product ; but the Grade 1 would 
mean prime physical condition, and the lower 
grades inferior physical condition. Eventually 
something like varietal names may be attached 
to those kinds of corns that, for example, grade 
fifteen per cent protein. The name would be a 
guarantee of the approximate content, as it now 
is in a commercial fertilizer. 

Closely allied to the corn-breeding work of Illi- 
nois (which is carried on by the Experiment Station 
and also by a commercial firm) is the wheat-breed- 
ing and flax-breeding work in Minnesota under 



216 RECENT OPINIONS. 

the direction of Professor Hays. Mr. Hays's aim 
has been chiefly to increase general value per acre. 
The following sketch is made from his notes : — 

Examples are given of increased efficiency in varieties 
produced at the Minnesota Experiment Station in coopera- 
tion with the U.S. Bureau of Plant Industry and other 
stations. 

Minn. No. 163 wheat was bred by selection from Fife 
parentage. During three years' comparison in field tests at 
University Farm, near Minneapolis, it averaged 2.7 bushels 
gain per acre, or eleven per cent better than its parent 
variety, as shown by the following table: — 

Minn. No. 163 28.5 bushels 

Fife parent 25.8 " 

Increase 2.7 

In 1899, this wheat was sold to one hundred farmers, 
thirty-eight of whom made the comparison between this and 
their common wheats in a manner fair to both. The follow- 
ing table shows the average increased yield to have been 1.4 
bushels per acre, or eight per cent : — 

Minn. No. 163, average yield 18.1 bushels 

Common wheats, average yield 16.7 

Increase 1-4 

In 1903, this wheat grew on at least 100,000 acres, and 
since it was first distributed it has produced $ 100,000 more 
than would have resulted from the varieties that it has 
displaced. 

Minn. No. 169 wheat was bred by selection from a Blue 
Stem foundation. During the first four years it was in our 
field tests it averaged 4.9 bushels more than the parent wheat, 
as displayed by the following table of average yields, showing 
an increase over its parent variety of twenty per cent : — 



THE FORWARD MOVEMENT. 217 

Minn. No. 169 28.5 bushels 

Minn. No. 01 .... 23.6 



Gain 4.9 " 

In 1902, this wheat was sent in four-bushel lots, at $1.50 
per bushel, to three hundred and seventy-five farmers. 
Eighty-nine reports gave comparisons that were fair both 
to the new and old wheats, and there were obtained the fol- 
lowing average yields, showing an increase over the common 
wheats for the entire State of eighteen per cent : — 

Minn. No. 169 21.5 bushels 

Common wheats 18.2 " 



Increase 3.3 " 

In 1903, more than 150,000 bushels of this wheat were 
grown, most of which will be used for seed in 1904. 

Similar results have been secured with flax. Seven years 
ago, Professor Hays chose seven samples of the common 
Minnesota and Dakota flax, and made by selection many 
new types for the production of seed, and numerous other 
types, especially for production of fibre. The following table 
gives the general results for 1902: — 

Yield of Yield of Height in 

Av. of 4 best varieties selected for seed 
Av. of 4 best varieties selected for fibre 
Av. of 4 best common varieties (from 
outside sources) .... 

Increase 5.9 .24 . . . 

In field trials, in 1902, the increased yield of flax per acre 
of the new varieties bred for seed was forty-nine per cent ; 
and the increased height of the new varieties bred for fibre 
was forty-six per cent more than the common flax. 



grain. 


straw. 


inches 


. 17.8 


1.40 


23 


. 10.5 


1.76 


35 


. 11.9 


1.52 


24 



218 RECENT OPINIONS. 

u We have developed statistical methods," Pro- 
fessor Hays writes, "of dealing with such plants 
as wheat, alfalfa, corn, and, in fact, nearly all of 
the field crops where it is necessary or very advan- 
tageous to plant a single seed in a hill, that selec- 
tions may be made and the breeding powers of 
parent plants measured. The general features of 
this statistical work may be stated as follows : 
Every acquisition or newly bred variety receives 
a number written thus, i Minn. No. 13 corn/ for 
example. It is also botanically described and the 
facts concerning its history, name, description, etc., 
entered in our 4 Minnesota Number Book.' If the 
newly secured variety is an exceptionally promising 
one, it is put into field tests, but ordinarily in the 
preliminary garden test the first year. Promis- 
ing acquisitions and promising newly bred hybrid 
stocks are entered in the nursery, where their 
breeding by rigid selection is begun, and large 
numbers of plants are grown, one in each hill, 
giving each plant the same space and opportunities 
as each other plant. By processes of elimination, 
the few best performers are secured. The next 
year we plant a large number of the progeny of 
each of these superior mother-plants. The aver- 
age yield, height, and other measures are taken of 
the progeny of each mother-plant. The breeding 
value of each mother-plant is thus secured in 
terms of the average performance of the progeny ; 



THE FORWARD MOVEMENT. 219 

these are better measures of breeding power than 
are the measures of mere performance of the indi- 
vidual. These tests of the breeding values of the 
mother-plants are continued two and sometimes 
three years. Seeds from parent plants producing 
the best average progeny are used alone or in 
mixtures of close-pollinated species, and in mix- 
tures in open pollinated species as the foundation 
of new varieties. These are tested in the field 
with the parent and other best standard varieties 
for three years. Any introduced or newly bred 
variety which is an especially good yielder of value 
per acre is sent to the cooperating State Experi- 
ment Stations in surrounding States and to our 
substations, and its quantity is rapidly increased. 
Any variety that is specially promising after being 
tried for, say, two years at several stations, is in- 
creased to sufficient quantity to sell to a number 
of farmers in each county in the State. This seed, 
backed by all the force of pedigree that we can 
command, is sold at a high price, so as to make 
the seed business profitable, and men are induced 
to raise it and sell large quantities at a price 
which will yield them a profit." 

A most gratifying augury of the coming type 
of effort is to be found in the work of the Plant- 
Breeding Laboratory of the national Department 
of Agriculture. This is an organization effected 
for the purpose of producing types or kinds of 



220 RECENT OPINIONS. 

plants that shall meet particular requirements. 
Its work is now proceeding with many groups of 
plants, but the burden of all its effort is efficiency in 
the final product. Its work with cotton promises 
to do nothing less than to revolutionize the cotton 
industry. The special difficulty with the present 
Upland cotton is the shortness of the " staple " or 
fibre. This inch-long staple sells at present (1903) 
for eight to eight and one-quarter cents a pound, 
whereas the long staple of the Sea Island cotton 
sells for twenty -five to thirty cents per pound. 
The effort is to secure a longer staple for the 
Upland, either by crossing it with the Sea Island 
or by working with some foreign long-staple type. 
The Egyptian cotton has a long staple, and this 
is now being used as one of the foundation stocks. 
But the Egyptian cotton possesses faults along 
with its long staple. It will be the work of years, 
by means of careful selection, to augment or main- 
tain the desirable qualities and to eliminate the un- 
desirable qualities ; when this is done, the cotton 
will no longer be the Egyptian, but practically 
a new creation, and this new creation should 
receive a new name in order to distinguish it 
from the inferior Egyptian from which it will 
have had its birth. Under the leadership of Mr. 
Webber, this new plant-breeding enterprise (prob- 
ably the largest in the world) is now extended to 
citrous fruits, apples, pineapples, oats, tobaccos, 



THE FORWARD MOVEMENT. 221 

and other crops ; and there is every indication 
that its usefulness will expand greatly within 
the immediate future. Other institutions, and 
other divisions of the Department of Agricul- 
ture, are conducting similar work. In fact, one 
or more officers at nearly every experiment station 
are now giving attention to some phase of plant- 
breeding work. It is significant that effort is 
now being given to the improvement of the staple 
farm crops, whereas a few years ago plant-breed- 
ing work was supposed to belong mostly to the 
horticulturist. Time is now on when every re- 
sourceful farmer must look to the improving of 
the intrinsic merits of his crops. 

The modern methods of plant-breeding demand, 
first, that the breeder shall familiarize himself 
thoroughly with the characteristics of the group 
of plants with which he is to work. He must have 
very specific and definite knowledge of what makes 
the plant valuable and what its shortcomings are. 
Then he must secure as starting-points plants that 
give promise in the desired direction. Thereafter 
his skill will be taxed in selecting along responsive 
lines, in making accurate and significant statistical 
measures, in devising workable systems of testing. 
He must grow large numbers of plants, if he is 
working with farm crops, in order to multiply his 
chances of securing desirable variations and to 
minimize the errors. 



222 RECENT OPINIONS. 

A promising course of breeding is one that shall 
develop disease-resisting races within the variety. 
Considerable progress has already been made in 
this direction with cotton, oats, and some other 
crops. Now and then a hill or a row or a variety 
of potato resists the blight. Why ? May it not be 
used as a starting-point for the development of a 
blight-resistant strain ? The producing of disease- 
resisting and pest-resisting races is one of the 
most promising lines of work in the new plant 
pathology. 

Nor are all these advances to be secured from 
seed selection alone. The cuttings and grafts of 
fruit plants perpetuate the parental characteristics 
with a good degree of surety. The time must 
soon come when it will not be sufficient to multiply 
the Bartlett pear from the Bartlett pear. We shall 
still further specialize our ideals and propagate 
from particular Bartlett pear trees that have made 
record performances. This subject is being tested 
in New York and elsewhere. It is one of the most 
important problems now before the nurseryman 
and orchard] st. 1 

All this plant-breeding work is especially of a 
kind to demand governmental support. The prog- 

1 See, for example, a discussion of this subject in a paper 
on "The Whole Question of Varieties," in the Report of the 
American Association of Nurserymen, 1903 (Detroit conven- 
tion). The subject is also discussed in " Survival of the Unlike." 



THE FORWARD MOVEMENT. 228 

ress of invention can be left to private initiative, 
because the person can patent his device and secure 
all the financial returns that it is worth. A variety 
cannot well be patented or controlled. This is par- 
ticularly true of these great race improvements, in 
which no distinct and namable variety results ; and 
these race improvements are the very ones that are 
most likely to be of greatest benefit to agriculture 
and therefore to the nation. 

These methods and ideals may all be summed 
up as follows : — 

I. Determining on what the merit in any group 
of plants depends, and finding out what is needed 
to make the plants more efficient. What makes a 
potato " mealy " ? 

II. Securing a start in the desired direction by 
(a) Choosing for seed-bearing any plants that 

are promising ; 
(6) Introducing prominent foundation stock 

from other regions or foreign countries ; 
(<?) Crossing for the purpose of injecting a 

new or better character into the strain. 

III. Continued selecting, careful testing, and 
keeping accurate statistical measurements and 
records to maintain the progress true to line. 

The first thing that strikes one in all this new 
work is its strong contrast with the old ideals. 
The "points" of the plants are those of "perform- 
ance " and " efficiency." It brings into sharp relief 



224 RECENT OPINIONS. 

the accustomed ideas as to what are the "good 
points v in any plant, illustrating the fact that these 
points are for the most part largely fanciful, are 
founded on a priori judgments, and are more often 
correlated with mere " looks " than with efficiency. 
An excellent example may be taken from corn. 
In "scaling" any variety of corn, it is customary 
to assume that the perfect ear is one nearly or 
quite uniformly cylindrical throughout its length 
and having the tip and butt well covered with 
kernels. In fact, the old idea of a good variety of 
corn is one that bears such ears. Now this ideal 
is clearly one of perfection and completeness of 
mere form. We have no knowledge that such 
form has definite correlation with productiveness, 
hardiness, drought-resisting qualities, protein, or 
starch content — and yet these attributes are the 
ones that make corn worth growing at all. Such 
ears may be more productive of kernels, but they 
may not be characteristic of plants that produce 
the greatest number of large ears. It may be dis- 
tinctly worth while to breed for this perfection in 
form, providing it is associated with breeding for 
efficiency. An illustration also may be taken from 
string beans. The ideal pod is considered to be 
one of which the tip projection is very short and 
only slightly curved. This apparently is a ques- 
tion of comeliness, although a short tip may be 
associated in the popular mind with the absence of 



THE FORWARD MOVEMENT. 225 

"string" in the pod; but we do not know how 
much this character is related to the efficiency of 
the bean pod. We are now undergoing much the 
same challenging of ideas respecting the " points " 
of animals. These "points," by means of which 
the animals are "scored," are often merely arbitrary. 
Now, animals and plants are bred to the ideals ex- 
pressed in these arbitrary points, by choosing for 
parents the individuals that score the highest. 
When it becomes necessary to recast our "scales 
of points," the whole course of evolution of domes- 
tic plants and animals is likely to be changed. 

We are to breed not so much for merely new 
and striking characters that will enable us to 
name, describe, and sell a "novelty," as to improve 
the performance along accustomed lines. We do 
not need new varieties of seedling potatoes so 
much as we need to improve, by means of selec- 
tion, some of the varieties that we already pos- 
sess. We are not to start with a variety, but 
with a plant. It is possible to secure a five per 
cent increase in the efficiency of our field crops ; 
this would mean the annual addition of hundreds 
of millions of dollars to the national gain. 

The purpose, then, of our new plant-breeding is 
to produce plants that are more efficient for spe- 
cific uses and specific regions. They are to be 
specially adapted. These efficiency ideals are of 
six general categories : — 

Q 



226 RECENT OPINIONS. 

1. Yield ideals. 

2. Quality ideals. 

3. Seasonal ideals. 

4. Physical conformation ideals. 

5. Regional adaptation ideals — as to climate, 
altitude, soil. 

6. Resistant ideals — as to diseases and insects. 

The main improvement and evolution of agri- 
culture are going to come as the result of greater 
and better crop yield and greater and better ani- 
mal production. It is not to come primarily from 
invention, good roads, rural telephone, legislation, 
discussion of economics. All these are merely 
aids. Increased crop and animal production are 
to come from two agencies : improvement in the 
care that they receive ; improvement in the plants 
and animals themselves. In other words, the new 
agriculture is to be built upon the combined re- 
sults of better cultivation and better breeding. 
So far as the new breeding is concerned, it is 
characterized by perfect definiteness of purpose 
and effort, the stripping away of all arbitrary 
and factitious standards, the absence of speculative 
theory, and the insistence upon the great fact that 
every plant and animal has individuality. 




Mendelism is maize. The first crossing was made in 1900, 
Stowell Evergreen being pollinated by Indian Flour corn. The 
ear resulting from this cross (1900) presented in color and com- 
position the characteristics of Indian Flour corn. This ear was 
planted in 1901. Some plants were pollinated in 1901 with Stowell 
Evergreen (one of the resulting ears shown at left) and some with 
the hybrid itself (a resulting ear on the right). —Plant-Breeding, 
Laboratory, United States Department op Agriculture. 



LECTURE V. 

CURRENT PLANT-BREEDING PRACTICE. 
[Contributed to the Fourth Edition, 1906.] 

One of the " signs of the times " in North Amer- 
ica is the attention that is being given to the practi- 
cal breeding of plants. The academic discussion 
of the subject is now well past, and a host of per- 
sons is actually at work. Results are accumu- 
lating rapidly with very many kinds of plants ; 
but most breeders are too busy with their enter- 
taining work to stop long with philosophy or specu- 
lation. Eventually, of course, we shall be able to 
formulate somewhat definite statements as to how 
to proceed to secure desired results, and then the 
literature of plant-breeding can be intelligently 
rewritten. However, there is no hope that plant- 
breeding can ever proceed with such exactness as 
to enable us to produce forthwith the things that 
we desire, in the way in which the mechanician 
devises new machines, notwithstanding all the 
suggestions of persons who write with much self- 
assurance. For all that we can now see, plant- 
breeding will always be an experimental process. 

227 



228 CURRENT PLANT-BREEDING PRACTICE. 

It is this very experimental uncertainty of the 
work that gives it much of its charm to inquisitive 
and sensitive minds. 

In considering the American achievement in 
plant-breeding, we must divest ourselves at the 
outset of all idea of "wonder," and "miracle," and 
other nonsense, which has been so much written 
into the subject in very recent time. Plant- 
breeding is a plain and serious business, to be 
conducted by carefully trained persons in a pains- 
taking and methodical way. It is not magic. 
There are persons who have unusual native judg- 
ment as to the merits and capabilities of plants 
and who develop great manual skill ; but they are 
plain and modest citizens, nevertheless, and their 
methods are perfectly normal and scrutable. The 
wonder-mongers are the reporters, not the plant- 
breeders. 

It is a curious psychological phenomenon that 
the populace, or a certain part of it, seems to lose 
its head now and then. This phenomenon is not 
peculiar to politics. It enters those domains that 
are compassed by fact and that in ordinary times 
are dominated by common sense. Plant-breeding 
has been seized of this sensationalism. News- 
papers, magazines, and books have spread the most 
wonderful tales. The lay writers have at last 
awakened to the fact that great progress is 
making in agricultural subjects, and, with a frag- 



THE THREE ESSENTIALS. 229 

mentary and superficial view here and there, have 
written of the subjects with all the enthusiasm 
and partiality of new discovery. I have now in 
mind not only the inflated writing about plant- 
breeding, which constitutes a regrettable contribu- 
tion to current horticultural literature, but also 
that general tendency to exploit everything that 
is capable of high coloring. I fear that the agri- 
cultural historian, when he takes account of the 
exploitations of the present day, will recall other 
stages in which we seem temporarily to have 
lost our better judgment, of which the Morus 
multicaulis craze and the lightning-rod boom are 
examples in two previous generations. 

Having now warned my reader that I have 
nothing marvellous in store, I shall proceed to 
indicate some of the ways in which American 
plant-breeders are working, fully conscious that 
the space at my disposal is much too little to allow 
of any adequate presentation of the subject. It 
may not be out of place to call the reader's atten- 
tion to the three foundations on which rests the 
increased productiveness of crops and animals : — 

The enrichment of the land ; 

The tillage and care ; 

The producing of better varieties and strains. 

We have long given careful attention to the first 
two ; now we are studying the third with new 
enthusiasm and purpose. There recently has been 



230 CURRENT PLANT-BREEDING PRACTICE. 

organized an " American Breeders' Association," 
of which three conventions have now been held. 
The proceedings of the first two meetings are 
published in one volume, and the list of members 
constitutes a breeders' directory ; this list contains 
seven hundred and fifteen names of plant-breeders 
and animal-breeders. In the classified "business 
directory " are the following numbers interested 
in different phases of plant-breeding : fruit and 
nursery stock, forty persons ; seed corn, twenty- 
nine persons ; farm seeds, twenty-four persons. 
This classified list is not at all complete. The per- 
sons that are interested in the breeding of flowers 
alone are probably more numerous than all of these. 
Local crop-breeders' societies are also being 
organized. The " Nebraska Corn Improvers' As- 
sociation " met recently at Lincoln, with the fol- 
lowing papers on the programme : — 

Breeding Cereals, Prof. C. A. Zavitz, Guelph, Ontario. 

Breeding Timothy, Dr. A. D. Hopkins, Washington, D.C. 

The Corn Plant as affected by Rate of Planting, E. G. Mont- 
gomery, Nebraska Experiment Station. 

Practical Corn Breeding on a Large Scale, J. Dvvight Funk, 
Bloomington, 111. 

Fundamental Requirements for Grain Breeding, Prof. M. 
A. Carleton, Washington, D.C. 

Breeding Drouth Resistant Crops, R. Gauss, Denver, Col. 

Value of Corn Pollen from Suckers vs. from Main Stalks, 
C. P. Hartley, Washington, D.C. 

Experiments in Wheat Breeding, Alvin Keyser, Nebraska 
Experiment Station. 



EXTENT OF PLANT-BREEDING. 231 

The most methodical plant-breeding is now 
being done by officers of the experiment stations 
in the United States and Canada, and by the 
United States Department of Agriculture. In 
most of the experiment stations there is one per- 
son interested in improving horticultural plants 
and another interested in field crops ; as there is 
an experiment station in every state and territory 
and in the provinces of Canada, it will be seen 
that there are more than one hundred persons 
who, by their profession, are directly concerned in 
plant-breeding, aside from a number of persons 
in the Plant-breeding Laboratory of the United 
States Department of Agriculture who devote 
themselves exclusively to this work, and not count- 
ing many persons in other branches of the Depart- 
ment who devote more or less of their energies 
to such subjects. The work is extended, also, 
into the hands of various assistants in the dif- 
ferent institutions ; so that it is probably no exag- 
geration to say that three hundred professional 
investigators are now giving attention, for a 
greater or less part of their time, to measures 
for improving American crop production by 
means of breeding. Aside from this, plant- 
breeding is now a subject for instruction in 
many of the agricultural colleges, and in this 
way the impulse is carried far and wide over the 
country. 



232 CURRENT PLANT-BREEDING PRACTICE. 

Long before these professional experimenters be- 
gan their work, however, patient and painstaking 
men had been breeding plants. They were " prac- 
tical " men ; that is to say, they bred varieties in 
order that they might sell the stock. Consider 
the number of named varieties, in the catalogues, 
of cabbages and tomatoes and dahlias and roses 
and strawberries : all these originated somewhere, 
and somebody named them and introduced them. 
To be sure, many of these varieties were discov- 
ered amongst other plants, no one knowing how 
or why they came ; but many of them, particularly 
in the roses and other florists' plants, were care- 
fully bred ; and even the fortuitous varieties were 
often improved and " fixed " by subsequent selec- 
tion. If one is to sell a novelty, he must name it. 
The tendency, therefore, was to produce a form 
distinct enough in general external characters to 
be easily distinguishable ; that is, to produce 
"varieties." The experiment station man, how- 
ever, is not pressed by the necessity of selling his 
product. Therefore he cares little for merely 
producing a new variety ; he may think it more 
important to improve some existing variety or to 
intensify some character that is not usable in gen- 
eral catalogue descriptions : in short, he seeks for 
efficiency and not for mere characters. This type 
of effort was explained in the third edition of this 
book, and the description will still be found in the 



STAGES IN PLANT-BREEDING. 233 

pages between 203 and 226. One might write a 
book on the plant-breeders who gave us the good 
old varieties that we still prize, working quietly 
and obscurely long before the days when periodi- 
cals cared to discuss the subject or before men of 
science condescended to investigate it. The pro- 
duction of varieties in those days was regarded 
as a trade secret, and this in part accounts for 
the small knowledge that we have had of the 
subject. I well remember the air of mystery that 
attached to the subject when I first began to in- 
quire into it, and the great difficulty of securing 
any publishable data even when I wrote this book 
ten years ago ; but now the field is open and free, 
many ardent young fellows are exploring it, and 
if I were to write again, I should be bewildered 
by the facts and instances that I should find. 

Before proceeding to the discussion of details, 
I may be allowed to remind the reader of the pro- 
cesses or stages in plant-breeding: — 

1. To determine what attributes it is desirable 

to work for; 

2. To secure a variation ; 

3. To improve and concrete the variation, if 

need be, by selection. 
It matters not whether the breeder is Darwinian 
or De Vriesian, the methods are practically the 
same. Even if varieties are mutants, as De Vries 
supposes, — forms small or great that originate 



234 CURRENT PLANT-BREEDING PRACTICE. 

f all-fledged, — we may still need to practise selec- 
tions as between mutants ; and if any varieties 
turn out to be amenable to further separation by 
means of selection, it only proves that these par- 
ticular forms are not mutants. If a form is so well 
marked and so valuable and so constant that it 
needs no selection, then the breeder may rejoice 
that his task is so easy, and he should have suffi- 
cient time and enthusiasm left to cause him to 
desire to repeat the experience. Howbeit, if the 
plant-breeder's realm lies with plants that he must 
propagate by means of seed, selection is usually 
the one essential to success. How the variations 
or differences are to be secured in the first place, 
— whether by change of soil or climate, hybridi- 
zation, or the less arduous method of merely 
watching for them if perchance they are in the 
mood to appear, — is a question to be settled each 
man for himself ; and he will likely find that there 
is no royal road, and in consequence he will try 
all methods and keeps his eyes open in the bar- 
gain. The greater the number of plants on which 
he experiments, the greater will be the likelihood 
of securing useful variation, and the more freely 
can he select ; all recent experience enforces this 
fact. 

By selection he hopes to cut off the undesirable 
forms and to cause the stock to " come true " to 
seed ; and he may also be able to intensify his 



HEREDITY IN AMARANTUS. 



235 



characters at the same time. To "come true," 
means that the particular attribute or form 
becomes hereditable. Sometimes the form is he- 
reditable in the beginning. I happen to have 
photographs showing such an example. It is the 
case of two red-root pigweeds, Amarantus retro- 




Fig. A. — The big pigweed, after frost. 

flexus, that grew in such a jostle of weeds that they 
had to take on different size and shape in order to 
live. A fuller account of these two pigweeds can 
be found on pages 258 to 263 of " Survival of the 
Unlike " ; it is now sufficient to say that one of 
them got headway above its neighbors and meas- 
ured thirty inches in spread and twenty-four inches 



236 CURRENT PLANT-BREEDING PRACTICE. 

in height, and that the other had a spread of nine 
inches and a height of twelve inches. The frame- 
work of the larger plant is shown in Fig. A. Seeds 
from both plants, equally mature to all appear- 
ances, were carefully sown in pans in the green- 
house ; those from the smaller plant germinated 
poorly, as seen in Fig. B ; and when the plants came 
into bloom, there was still a marked difference, as 
shown in Fig. C. I have no reason to doubt that 
these differences would have been again heredi- 
table to some degree had I sown the seed ; but as I 
had not set out to produce an improved strain of 
pigweed, I did not carry the test farther. All 
this suggests a method of securing such a plant as 
you may want. 

The material for new types of plants may be 
(a) the varieties already in use, (5) species or 
varieties introduced from foreign parts, (V) native 
plants not yet domesticated, (d) hybrids. In the 
introduction of foreign plants, the past few years 
have been fertile. These plants are introduced 
primarily for their intrinsic merits ; but almost 
immediately they are established in the new coun- 
try, they begin to change or vary, and soon form 
the basis of new direct forms or of hybrids. These 
foreign plants are being brought in by commercial 
firms, well-to-do plant fanciers, botanic gardens, 
experiment stations, but particularly by the United 
States Department of Agriculture, which has or- 



HEREDITY IN AMARANTUS. 



237 




Fig. B. — Seedlings from the small pigweed at the left, and from 
the hig one at the right. 




Fig. C. — The pigweeds at blooming time. The parental character- 
istics — apparently the work of a single generation — are shown 
to be hereditable. 



23& CURRENT PLANT-BREEDING PRACTICE. 

gaiiized for this purpose the " Office of Seed and 
Plant Introduction and Distribution," in charge 
of David Fairchild. This office introduces prom- 
ising plants from all parts of the world, and 
subjects them to test on the grounds of the De- 
partment of the various experiment stations, and 
on the premises of private persons. Over fourteen 
thousand selected entries appear on the inventory 
of the office. Some of these entries are species 
new to the country ; but most of them are new or 
untried forms of species already growing in North 
America. In many ways our domestic flora is 
being enriched from outside sources, and these 
additions in time will give rise to a variable 
progeny, or will furnish strong stock for hybridi- 
zation, and will affect the course of plant-breeding. 

I. Luther Burbank. 

, An editor of one of the great magazines asked 
me recently whether Luther Burbank were the 
only plant-breeder in the country. One who has 
read the current Burbankiana can well under- 
stand why the question was asked. If any reader 
has followed me this far, he will not need to ask a, 
similar question. 

Yet if there are other plant-breeders, Luther 
Burbank stands alone. He is a private person, 
pursuing his work in his own way, and be- 
cause he loves it so well that he cannot forego 



LUTHER BUEBANK. 239 

it. He is a gardener of a new kind. Every 
plant appeals to him. This appeal is quite unlike 
the appeal that is made to the botanist or even to 
the horticulturist ; Burbank likes it because it is 
a plant and because he would like to try to modify' 
it. Therefore he grows everything he can, no 
matter where it comes from or of what kind. 
He cultivates with personal care, multiplies the 
stock to the limit of his capacities, scrutinizes 
every variation, hybridizes indiscriminatingly, 
saves the seeds of the forms that most appeal to 
him, sows again, hybridizes and selects again, 
uproots by the hundreds and thousands, extracts 
the delights from every new experience, and now 
and then saves out a form that he thinks to be 
worth introducing to the public. Every part of 
the work is worth the while of itself ; at every 
stage the satisfaction of it is reason enough for 
making and continuing the effort. Every form is 
interesting, whether it is new or the reproduction 
of an old form. He shows you the odd and inter- 
mediate and reversionary forms as well as those 
that promise to be of use to other persons. 

In all this there is neither magic nor conjura- 
tion. The methods are the common practices of 
all good plant-breeders, made unusually efficient, 
perhaps, by the geniality of the climate, the great 
scale on which some of the work is conducted, the 
wide variety of plants under experiment, and the 



242 CURRENT PLANT-BREEDING PRACTICE 

patient skill and good judgment of the man. He 
cares little for the scientific method, so long as 
the plants produce new forms. He will try to 
cross anything, no matter whether it has ever 
been crossed before or whether the crossing is 
in utter disregard of all acknowledged botanical 
relationships. Once when I asked him the botani- 
cal name of a plant, he replied that he did not 
know and did not care to know ; for if he knew 
he would likely be bound by the book statements 
and he might be handicapped in his work. He 
is a bold worker, and this accounts for some of the 
odd results. 

Mr. Burbank is a plain, modest, sympathetic, 
single-minded man. He is not a wizard. The 
reporters have got hold of him and have abused 
their privileges because they have not known how 
to measure him and have not understood him. 
Perhaps he has not understood himself. He is 
kind-hearted and obliging ; he has been drawn 
into discussions of all kinds of subjects, some of 
which nobody knows anything about ; and persons 
have been led to think that he has occult knowl- 
edge. So far as these write-ups have tended to 
draw attention to the kind of work that he is 
doing, they undoubtedly have served a useful pur- 
pose ; but many of them have really misrepre- 
sented the genius of the man. Luther Burbank 
stands for a great new idea in American horti- 



LUTHER BUKBANK 243 

culture, and it is time that we begin to recognize 
what this is. 

The practical results that Mr. Burbank has se- 
cured have been praised beyond all reason. His 
place abounds in interesting and surprising things, 
just as would be expected of any other man's place 
if conducted under similar conditions. His work 
has been so much written about that it is not nec- 
essary to try to make any catalogue of the things 
that are under his hand. The number of really 
useful things that have been introduced by Bur- 
bank is proportionally small ; although it is not 
too much to hope that some of his productions, as 
the plumcots, may be the starting points of strong 
and novel lines of evolution. Some of those that 
have been most heralded are of doubtful economic 
value. This is true, I think, of the much- vaunted 
spineless cactus. Several species of opuntia (to 
which genus Mr. Burbank's spineless cactus be- 
longs) are spineless. Spineless cacti have long been 
known in Mexican and other gardens. By con- 
tinued selection the more or less spineless forms 
can be singled out and the smooth character per- 
haps intensified. Mr. Burbank may be able to 
eliminate the small spicules and to improve the 
plant in the edible qualities of its fruit and stems. 
There is no doubt that he has the spineless 
cactus in quantity (Fig. F). It is a pleasure 
to see him rub his face against the pads to deter- 



LUTHER BURBANK 245 

mine whether the spines are really there. But 
what use shall we make of it ? It is said that we 
shall plant the deserts, for the cattle can eat this 
spineless cactus, and thus will the food supply of 
mankind be immensely multiplied and the welfare 
of the race enhanced. The cattlemen now singe 
the spines from the wild cacti by means of gaso- 
line torches, and this is much cheaper than to 
plant the desert ; and experiments show that if 
the desert were planted with spineless cacti, the 
young plants would be destroyed if the cattle 
and jack-rabbits were allowed on the ranges : this 
would mean fencing the deserts. If the spineless 
cacti are grown from seeds, some of the progeny 
will probably be spiny ; these and the native 
seedlings will have to be uprooted and this 
will probably entail more expense than the en- 
terprise will be worth. If, in addition to this 
weeding, the plants are set out from cuttings, the 
desert becomes practically a cultivated ground. 
Moreover, it is undetermined whether Mr. Bur- 
bank's cactus is really a desert form. Some of the 
deserts will be irrigated and then cacti will not 
be wanted ; and if the deserts are to be planted at 
all, it is a question whether cacti are the best 
plants with which to stock them. 

All this leads me to say that the value of Mr. Bur- 
bank's work lies above all merely economic consid- 
erations. He is a master worker in making plants 



246 CURRENT PLANT-BREEDING PRACTICE 

to vary. Plants are plastic material in his hands. 
He is demonstrating what can be done. He is 
setting new ideals and novel problems. Hereto- 
fore, gardeners and other horticulturists have 
grown plants because they are useful or beautiful : 
Mr. Burbank grows them because he can make them 
take on new forms. This is a new kind of pleas- 
ure to be got from gardening, a new and captivat- 
ing purpose in plant growing. It is a new reason 
for associating with plants. Usually I think of 
him as a plant-lover rather than plant-breeder. 
It is little consequence to me whether he produces 
good commercial varieties or not. He has a sphere 
of his own, and one that should appeal to a univer- 
sal constituency. In this way, Luther Burbank's 
work is a contribution to the satisfaction of living, 
and is beyond all price. 

II. A Practical Plant-breeder. 

There are many wise and humble folk in many 
parts of the country who are making efficient his- 
tory in plant-breeding. I often feel that I should 
like to hunt them out and make them known to 
the world. The}^ are mostly plant-lovers, whose 
chief reward is the joy that they derive from the 
work. I was struck with this many years ago 
when making a study of the evolution of the native 
plums, for patient souls had been at work on these 
fruits for years almost unknown of the world at 



A PRACTICAL PLANT-BREEDER. 247 

large, and had produced numbers of useful varie- 
ties ; and I have been similarly impressed in other 
excursions into plant evolution fields. 

There is another class of practical men who do 
their work on a larger scale as a part of a thorough- 
going and well-known business enterprise. Such 
a business I am now to portray. I choose 
this particular instance only because I am some- 
what familiar with it and because it is near home. 
I had this man in mind when I wrote the lines 
on beans on pages 135 and 136 of this book. 

N. B. Keeney, Leroy, New York, was first a 
farmer. In war time he engaged in the produce 
business in Leroy, in a farming community. 
There was good trade in beans. The son Calvin 
N. Keeney became interested in the varieties of 
beans. He was attracted by their behavior in the 
field, and he began experiments to improve them 
by means of selection. From this it was but a 
step to the originating of new varieties. The son 
was taken into the business, the firm becoming 
N. B. Keeney and Son. The father is now dead, 
but the son continues the business. The business 
is primarily the growing of seed for seedsmen. It 
is devoted entirely to beans and peas. About two 
thousand acres in New York are devoted to beans, 
and four thousand acres in Michigan to peas. 

In connection with the seed business is a can- 
ning factory, putting up beans, peas, and sweet corn. 



248 CURRENT PLANT-BREEDING PRACTICE. 

The straw, husks, and other refuse could not be 
sold to advantage. It required an expenditure of 
five hundred dollars a year to dispose of the waste. 
In order to utilize this waste of the seed and canning 
businesses, a stock-feeding enterprise was estab- 
lished. The green pea vines, and corn refuse are 
ensilaged. The bean straw is fed to sheep. At pres- 
ent, the stock feeding comprises about one hundred 
and fifty hogs, three hundred steers, fifteen hun- 
dred sheep. These statements are made in order 
that the reader may see how far a bean-breeding 
and pea-breeding enterprise may lead. 

The main effort of the Keeney seed business is 
given to growing the leading varieties in quantity ; 
for in order to hold the best trade, it is necessary 
to keep every variety up to standard or even to im- 
prove it : therefore the entire enterprise becomes 
a practical plant-breeding business. Now and 
then new varieties are bred up and introduced ; 
and improved strains of old varieties are offered, 
often replacing entirely the old strains. In 1905 
the following varieties of beans were grown 
in quantity ; those marked with one star (*) are 
improved or selected strains, and those with a 
double star (**) are varieties of the Keeneys' 
originating : — 

Best of All. *Black Wax, Cylinder Pod. 

Bismarck, Buist's. **Black Wax, Fuller's. 

Black Wax, Challenge. *Black Wax, Imp'd Prolific. 



A PRACTICAL PLANT-BREEDER. 



249 



♦♦Black Wax, Pencil-pod. 

Bountiful. 
♦♦Brittle Wax. 

Brown Bunch. 
♦♦Butter Wax, Maule's. 

Champion Bush, Low's. 

China Red Eye. 

Crystal Wax. 

Davis Wax. 

Emperor of Russia. 

Flageolet Wax, Crimson. 

Flageolet Wax, Purple. 

Golden Crown Wax. 

Golden Eyed Wax. 

Golden Wax, Grenell's Imp. 

Golden Wax, Orig. Strain. 
♦♦Golden Wax, Keeney's 
Rustless. 

Goddardor Imp. Hort.Dwf. 

Hodson Wax. 

Horticultural Dwarf. 

Hort. Dwarf, Carmine Pod. 

Hort. Pole, Worcester Imp. 

Hort. Pole, Gold. Carmine. 

Hort. Wax, Rawson's. 

Imperial Wax, Allen's. 

Imperial Wax, Jones's. 

Kidney, White. 

Kidney Wax, WardwelFs. 
♦♦Kidney Wax, Round Pod. 

Longfellow. 

Marrowfat, White. 
♦Medium, Burlingame's. 

Mohawk, Early. 



♦♦Mohawk Wax. 
♦*Pea Beans, Boston Small. 
Pea Beans, Snowflake. 
Perfection Wax. 
Prolific, Powell's. 
Prolific, Southern. 
Refugee, Extra Early. 
Refugee, Golden. 
Refugee, McKinley. 
Refugee, Round Pod or 

1000 to 1. 
Refugee, Silver. 
♦Refugee Wax, Keeney 
Stringless. 
Rust Proof Wax, Currie's. 
♦♦Saddle BackW ax, Burpee's. 
Scotia. 

Six Weeks, Long Yellow. 
Six Weeks, Round Yellow. 
♦♦Stringless Green Pod, 

Burpee's. 
♦♦Stringless Green Pod, Giant. 
Valentine Black. 
Valentine Ex. Ey. Red. 
♦Valentine, Ex. Ey. Ex., 
Round Podded Red. 
Valentine, Hopkins's Red. 
Valentine, White. 
Warren Bush. 
White Wax. 
♦♦White Wax, Burpee's New 
Stringless. 
White Seed Wax, Jones's. 
♦♦Yosemite Mammoth Wax. 



250 CURRENT PLANT-BREEDING PRACTICE. 

This list is interesting as showing the propor- 
tion of new or original to old or other varieties 
in a practical seed-breeding establishment. This 
list does not represent the whole number of varie- 
ties that Mr. Keeney grows, for the seed-breeder 
must test every new thing in his line and always 
be on the lookout for the chance to better the 
kinds that are in existence. Every year Mr. 
Keeney grows about two hundred kinds of beans 
in the test garden ; and sometimes as many as six 
hundred different lots — some of them represent- 
ing different stocks or strains of the same variety 
— are grown and studied. 

To make any intelligent headway in breeding 
beans, the breeder must first know beans. He 
must know what the people want, what it is pos- 
sible to get, and all the good points and bad 
points of beans as to root and top, and bloom and 
pod and seed. This will prevent laborious mis- 
takes and economize much enthusiasm to be put 
into progressive work. Then he will look for 
natural sports that have some or all of the desired 
qualities ; thereafter the process is one of most 
rigorous selection until the stock breeds true. 
If the desired form or start does not appear, it 
may be necessary to set it off by crossing plants 
that have some of the desired characteristics; 
thereafter the process is one of selection, as 
before. Mr. Keeney says that he can increase 



A PRACTICAL PLANT-BREEDER. 251 

or intensify a characteristic by means of selection, 
as well as eliminate the undesirable features. 
This is the whole plan of Mr. Keeney's work. 
There is no mystery about it ; but there is judg- 
ment of a kind that few men possess and a per- 
sistent process of selection such as few men have 
the heroism to maintain. 

If the breeder burns with a desire to have 
forms so distinct that he can attach a new name 
to them, he must caution himself at every point, 
else he will be introducing things before they are 
ready or which are of no gain to the world. New 
varieties of seed vegetables come slowly ; and if 
they are not well bred (that is, not well selected), 
they will very soon break up into other forms or 
u run out." Mr. Keeney puts his main effort in 
keeping the old varieties up to grade, and it is on 
these varieties that he makes the business pay. 
The making of new kinds of beans pays only in 
the intellectual satisfaction of it, and in the 
general standing that it gives the business. Mr. 
Keeney tells me that if he had never accomplished 
anything else in the breeding of plants, he would 
be content with having produced the Burpee 
Stringless Green Pod. 

To keep the stock up to grade, it is necessary 
to begin with seed that is not only "true to 
name," so far as general varietal characteristics 
are concerned, but that is vigorous and with 



252 CURRENT PLANT-BREEDING PRACTICE. 

strong hereditary or carrying-over power. This 
seed is planted on well-prepared land that is 
adapted to beans. The tillage and general care 
must be of the best. The plantation is gone over 
with great care for "rogues" or untrue plants; 
these are pulled out. The thoroughness and con- 
sistency with which the " roguing " is done, will 
determine the result. This process is continued 
every year ; and if one field or one man's growing 
gives a better stock than any other, this product 
is used as stock-seed for all fields next year : thus 
the stock is always being renewed and rebred. 
Sometimes a single plant will be unusually good, 
and from this the whole stock may be renewed. 
For example, all the Mammoth-podded Sugar peas 
grown in America to-day came from a teaspoon- 
ful of seed that Mr. Keeney planted some ten or 
twelve years ago. 

Some fifteen or twenty years ago, Mr. Keeney 
found in a field of White Wax beans one plant 
that bore black seeds in stringless white pods. 
In three or four years he had saved a quart of 
promising seed. He planted this seed in an iso- 
lated rich farm garden. All came true but one 
plant : this plant was very tall and rank, and was 
green-podded. From this plant twenty-two 
varieties were produced, some of which were good 
enough to save and introduce. From the bulk 
of the original quart that came true, Mr. Keeney 



A PRACTICAL PLANT-BREEDER. 



253 



produced the Yosemite Mammoth Wax, which is 
now a standard variety. The introducing of the 
" stringless " character into his beans has come 
about very largely by crossing with the Yosemite. 
In peas, Mr. Keeney grows the following list 
in quantity (he has specially selected strains of 
those marked with a star *) : — 



Abundance. 

Admiral. 

Admiral Dewey. 

Advancer. 

Alaska. 

Ameer. 

American Champion. 
* American Wonder. 

British Wonder. 

Champion of England. 

Claudit. 

Daisy, Carter's. 

Duke of Albany. 

Duke of York. 

Dwarf Champion. 

Dwarf Telephone. 

Empire State. 

English Wonder. 

Everbearing. 

Excelsior, Gregory's. 

Excelsior, Nott's. 
*Extra Early, Pedigree. 

Extra Early, Trial Ground. 

First and Best. 

Forcing, Sutton's. 



Forty Fold. 

Glory. 
*Gradus or Prosperity. 

Green Gem, Sutton's. 

Heroine. 

Hurst, William. 

Ideal, Sutton's. 

Juno. 

King of the Dwarfs. 
*Laxton, Thomas. 

Long Island Mammoth. 

Market Garden, Horsford's. 

Marrowfat, Black-eyed. 

Marrowfat, Early Marble- 
head. 

Marrowfat, Improved Sugar. 

Marrowfat, White. 

May Queen. 

Perpetual. 

Premium Gem. 
*Pride of the Market. 

Prince of Wales. 

Profusion. 
*Prolific Early. 
*Prolific Early Market. 



254 CURRENT PLANT-BREEDING PRACTICE. 

Prolific, Laxton's. Sugar, Very Dwarf. 

Prosperity or Gradus. *Sugar, Mammoth Podded. 

Reliance, Hurst's. Sugar, Tall Gray. 

Seedling, Sutton's. Surprise, Gregory's. 

Senator, Improved. Telegraph (L. I. Mam). 

Shropshire Hero. ^Telephone. 

*Stratagem. *Tom Thumb. 

Sugar, Dwarf Gray. Yorkshire Hero. 

The familiar Extra Early garden pea has been a 
subject of very careful breeding. The " Pedigree " 
strain has a continuous genealogy running back 
to 1890. In that year, it became apparent to Mr. 
Keeney that the general stock of this well-known 
variety was much mixed and run down. He 
therefore selected out a good stock, and soon de- 
veloped some twenty-four " families " or lines of 
this variety ; from these he later selected three 
lines, which were equally desirable, and repre- 
sented very closely his ideal of what the Extra 
Early should be. He still keeps up the selection ; 
and two or three times has discarded all his gen- 
eral seed-stock which he had himself produced, and 
has renewed the stock with a strain that he had 
been breeding up in the meantime. The work of 
choosing the initial departures and of making the 
primary seed-stock selections cannot be left to 
hired men ; in fact, there are very few foremen 
or assistants who have the judgment and patience 
for the work : it must be a labor of love. Most 
persons do not have the courage to discard so 



PLANT-BREEDING IN EXPERIMENT STATIONS. 255 

many plants. Mr. Keeney says that the success 
in seed-breeding lies in what you throw away. 

The satisfactory prosecution of all this work 
requires careful note-taking. Mr. Keeney fur- 
nishes, for example, such information as that 
given on page 256 for his customers, all taken 
directly from field notes. 

There must also be personal records of the 
strains and stocks that are under manipulation. 
Mr. Keeney has kept the notes of his bean breed- 
ing in a specially prepared record book, with the 
entries running across two facing pages. The 
headings of the various columns on these two 
pages suggest the kind of information that the 
breeder desires to have. (See page 257.) 

III. The Experiment Station Work. 

Most of the agricultural experiment stations — 
and there is one to every state, territory, and 
nearly every Canadian province — are interested in 
concrete pieces of plant-breeding work. Through 
the extension work of these stations and of the 
agricultural colleges, the plant-breeding concep- 
tion is being carried to the people. These insti- 
tutions are distributing selected and highly 
bred seeds, and are instructing their corre- 
spondents in the importance of quality in seed 
stock and the conditions that modify that quality. 
Perhaps the most fruitful extension work of this 



256 



CURRENT PLANT-BREEDING PRACTICE. 



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258 CURRENT PLANT-BREEDING PRACTICE. 

kind is that conducted by the Ontario Agricultural 
College through the Ontario Agricultural and Ex- 
perimental Union. This is an organization of offi- 
cers, students and ex-students of the college. It has 
been in existence something more than twenty-five 
years. Through this union, since its organization, 
37,416 experiments or tests on agriculture alone 
have been conducted on the farms. The college 
has given much attention to the testing of the 
varieties of farm crops. Importation of the vari- 
ous cereals was begun twenty-five or thirty years 
ago. The institution has tested more than two 
thousand varieties of farm crops for a term of five 
years or more, some of them having been followed 
more than ten years. The college thus has on 
hand a vast amount of carefully tested and selected 
material with which to prosecute the cooperative 
work. The plan has been to choose from two to four 
of the most successful varieties of the various farm 
crops and put them out among the cooperators 
throughout the province. The college has under 
test at the present time two hundred varieties of 
potatoes from which selections are made for the 
cooperative tests. It has fifty varieties of sweet 
corn under study, and in nearly all of the farm 
and horticultural crops it is in a similar situation 
as regards material for the cooperative work. So 
far as the mere testing of varieties of ordinary 
farm crops is concerned, relatively little will be 



WORK IN ONTARIO. 259 

done in the future ; but the purpose is to continue 
the work with strains of those varieties that are 
the result of careful selection at the college. 
Several years ago work was begun in selecting 
wheat, barley, oats, and other grains by individual 
plants and in propagating these plants until a sup- 
ply was secured for the farmer. This year there 
were harvested two acres of oats that came from 
a single seed three years ago. It is remarkable 
that such a supply can be secured in so short a time. 
In 1905 there was secured a yield of 1929 pounds of 
barley and of 3439 pounds of oats that were the 
progeny of a single seed sown in 1903. It is also 
stated that for the more remote future the work 
will be with hybrids which they are now breed- 
ing with apparent success to produce more desir- 
able types with larger yielding qualities. All 
tests made by the farmers are duplicated on the 
college grounds. It is now proposed to establish 
a complete set of such experiments in each county 
in the province, the party conducting the work 
to be remunerated for the actual labor involved. 
These statements show how extended and effec- 
tive certain kinds of practical plant-breeding 
work have come to be. 

An examination of the recent annual reports of 
the experiment stations in the United States show 
that at least twenty-eight of them report specific 
plant-breeding work as in progress. The plants 



260 CURRENT PLANT-BREEDING PRACTICE. 

that are mentioned comprise the following : cot- 
ton, sorghum, corn, grasses, buckwheat, millet, 
wheat, rye, oats, barley, eggplant, tomato, red 
clover, tobacco, sweet corn, sugar beet, timothy, 
alfalfa, potato, pea, bean, apple, peach, cherry, 
plum, strawberry, blueberry, grape, date, buffalo- 
berry, currant, gooseberry, raspberry, ornamental 
shrubs, flowers, forest trees. 

It would manifestly be impossible to give even 
a running sketch of all this interesting plant-breed- 
ing work. Results may not be forthcoming as 
rapidly as we would like, but it is apparent that 
such an amount of effort concentrated on one gen- 
eral line of effort is bound to accumulate surprising 
results in the years to come. Merely as examples 
of the nature of the problems lying in this unex- 
plored field, I insert a brief description of two 
pieces of breeding work now in progress and very 
different in kind. 

Breeding Hardy Fruits for the Prairie Northwest. 

By N. E. Hansen. 

There are three headings under which this 
subject may be considered : (1) importation; (2) 
exploration ; (3) amelioration. By importation 
we secure the best plants from other countries. 
In pursuance of this policy I import plants every 
year from various countries of the Old World. 



FRUITS FOR DAKOTA. 261 

By exploration is meant searching for desirable 
variations from the normal type of fruits in our 
native woods and prairies. I have done much of 
this kind of work, especially in the range country 
from the Missouri River west to the Black Hills. By 
amelioration is meant the improving of this mate- 
rial gathered from various parts of the world. 
We should take all native plants of any value 
and try by crossing them with desirable imported 
plants to secure new plants combining the desir- 
able characteristics of both races. 

Over a large area of the prairie Northwest, 
many of the fruits grown in the eastern and 
southern states are deficient in hardiness. This 
has been demonstrated by thousands of planters. 
It has been estimated that it cost over one hun- 
dred million dollars to learn that the varieties of 
apples from the milder climate of western and 
southern Europe are not adapted to this new prairie 
region. It begins to be evident that all this ex- 
perience is another proof of De Candolle's law, that 
several thousand years are needed to produce a 
modification in a woody plant which will enable 
it to support a greater degree of cold. But that 
nature is equal to such a task is shown by the fact 
that woody plants, such as box elder and the red 
cedar, extending over a wide area, differ greatly in 
hardiness. The red cedar and box elder from the 
southern and eastern range of their limits winter- 



262 CURRENT PLANT-BREEDING PRACTICE. 

kill at the northern limits, while the local form of 
the species is hardy. In other words, it is possible 
for nature through thousands of years to change 
the constitution of a plant as to its ability to 
endure greater cold, but it is not an experiment 
for man to undertake. Inherent hardiness must 
be present in at least one of the parents of the 
seedling ; that is, hardiness cannot be secured 
from tender varieties by selection. It must either 
be present in both parents or transmitted from 
one parent, the same as any other characteristic. 
Plants can be bred more resistant to cold by cross- 
ing with some hardy species. 

Methods of Work. — In general, where no cross- 
ing is done, the principle followed is that laid 
down by Darwin and others : " Excess of food 
causes variation." Choice seedlings are started in 
flats and transplanted to the field when large 
enough, in highly manured soil. In some cases 
it is best to sow seed thinly in nursery rows and 
transplant when one year old. At fruiting time 
the best few are selected, the remainder dug with 
a tree-digger and destroyed by fire. 

After endeavoring in vain for several years to 
cross fruit blossoms in the breezy climate of 
South Dakota, where spring is sometimes back- 
ward and then the blossoms come on with a rush, 
I decided to do the work under glass. While 
visiting orchard houses in Europe in 1894 and 



FRUITS FOR THE COLD PRAIRIES. 263 

again in 1897 the thought came to me that this 
method of raising fancy fruit could be utilized in 
experiments in the prairie Northwest. The appli- 
cability of this method elsewhere remains to be 
determined. The use of dwarf stocks is necessary 
as the paradise for the apple, quince for the pear, 
and the western sand cherry for the stone fruits. 
The South Dakota legislature of 1901 granted 
means for erecting the first fruit-breeding green- 
house ever constructed. Since then experiments 
have been limited only by the space available. 
Much more could have been done with a larger 
greenhouse. I trust that future legislatures will 
provide additional facilities. Illustrations and de- 
scriptions of these breeding houses may be found 
in Bulletin 88 of the South Dakota Experiment 
Station. 

As a result of this appropriation, and the lib- 
erality of the regents of education in affording 
needed storage cellars and other facilities, we are 
able to announce the production of many inter- 
esting hybrid fruits, many of them combinations 
made for the first time. Some of them are hybrids 
of the South Dakota sand cherry with the peach, 
nectarine, Japanese plums, a Chinese apricot, and 
a purple-leaved plum from Persia. The work 
with the western Sand Cherry (Prunus Besseyi) 
is reported in Bulletin 87. Progress is also being 
made in originating hardy cherries, strawberries, 



264 CURRENT PLANT-BREEDIXG PRACTICE. 

and raspberries. By far the most extended ex- 
periment on record in the making of graft-hybrids 
of the apple has been undertaken, and we await 
the fruiting of the resulting plants with interest. 
In ornamentals the main work done has been cross- 
ing the wild Dakota and Siberian roses with choice 
doable roses. If sufficient greenhouse facilities 
are afforded, the propagation of such new seed- 
lings as give promise of permanent value will be 
pushed, so that they may be distributed for trial 
elsewhere as rapidly as possible. The advancing 
northward at least five hundred miles of the suc- 
cessful cultivation of the cherry, peach, and apri- 
cot, and that of winter apples, we trust will be 
some of the results of erecting this novel work- 
shop for the invention of new hardy fruits. 

Considerable success has been secured in has- 
tening the fruiting of cross-bred seedlings. For 
instance, strawberries originated one winter by 
crossing the wild with the tame have been raised 
up to fruiting size the same year outdoors and 
fruited in pots under glass the following winter. 
This saves much time in selecting varieties for 
propagation, and also hastens the work of propa- 
gation by our being able to pot many layers before 
transplanting to the field. 

In handling a quarter of a million fruit seed- 
lings, I find many interesting side lines of investi- 
gation presenting themselves, but just now the 



FRUIT-BREEDING IN DAKOTA. 265 

main effort must be to originate a few varieties 
of the various orchard and small fruits worthy of 
a permanent place on the present limited fruit list 
of the prairie Northwest. 

In handling so many thousands of seedlings, 
my endeavor in recent years has been to get some 
clew to the quality of the fruit while the plants 
are yet small. It would greatly lessen the labor 
involved. No positive correlations of this kind 
have as yet appeared. However, the two essen- 
tials of vigor and perfect hardiness are insisted 
upon from the beginning. With the sand cherry, 
of which I have a patch of over twenty-five thou- 
sand plants of the third generation under cultiva- 
tion coining into bearing in the year 1905, I have 
found some seedlings that are quite free from 
mildew which so commonly affects the plant, es- 
pecially in moist seasons. It is my belief that we 
can breed a mildew-resistant race of this prom- 
ising prairie fruit. In a patch of over six thou- 
sand native plum seedlings I insisted on, as far as 
possible, perfect foliage as well as fruit of large 
size and good quality. In a patch of over three 
acres of strawberries of half-wild, half-tame ances- 
try, I insist on the leaves being free from rust 
(Ramularia), but it may be impracticable to do 
this wholly as. our wild strawberries have the 
foliage affected in this manner. Whether we get 
our blight-proof apple remains to be seen. Any 



266 CURRENT PLANT-BREEDING PRACTICE. 

plant that will not endure forty degrees below 
zero with the ground bare of snow and come out 
unharmed the next spring is rejected. In disease 
resistance some peculiar facts crop out. For ex- 
ample, some pure wild roses mildew, while their 
lrybrids with cultivated roses are free. 

I have learned to look upon a species of plants 
only as a bundle of characteristics, more or less 
definite in its make-up, to be modified to suit our 
needs. A new seedling is really a new invention. 
Although legally " a gift of God," it is the result 
of the creative forces of nature under the guiding 
hand of man. Part of our labor is to improve 
nature's handiwork the better to adapt them to 
the needs of a civilization ever growing more 
complex. 

Cornell Timothy -breeding. 
By Samuel Fraser. 

The prosperity of a good part of the country 
rests directly on grass. Timothy grass is the most 
important single crop in New York State. Yet 
Ave have no varieties of timothy, as there are 
of wheat and corn and beans. No good farmer 
would sow wheat without knowing the variety, 
for varieties differ in yield, hardiness, quality of 
grain, or other excellences. The experiment sta- 
tion of Svalof, Norway, has shown that the yield 
of timothy, for hay, may be considerably increased 



TIMOTHY-BREEDING. 



269 



by the selection of varieties. It is to be expected 
that plants possessing other permanent characters 




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ft 



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ci 
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of economic value may be found, and that we may 
secure some varieties which will be early in bloom 



270 CURRENT PLANT-BREEDING PRACTICE. 

and others which will mature later ; some possess- 
ing strong and long stolons and practically no 
conn, and therefore adapted to withstand grazing; 
and still others which produce abundance of fall 
feed. 

A careful study of timothy will show that it is 
not all alike. It varies greatly ; it is reasonable 
to expect that some of these variations are heredi- 
table, and that this hereditability can be inten- 
sified or "fixed." In order to test these points, 
an experiment was begun in 1903. Timothy seed 
was secured from 230 sources in this country and 
abroad. With some selections made from indi- 
vidual plants on the University farm, 12,600 
plants were set in the fall of 1903 in 300 plats. 
During 1901 and 1905 the planting of progeny, 
selected for various characteristics, has increased 
the number of plats to about 450, with 20,000 
individuals. These, with a grass garden in which 
there are 6000 individual plants of about 50 
species, many being the progeny of selected 
plants, cover about 10 acres of ground. There 
are 20 miles of rows of timothy plants. More 
than 100,000 distinct records have been recorded 
in a single year on 9000 of these plants. 

All plats contain 42 plants, 30 inches asunder 
in rows 30 inches wide and in 2 rows of 21 each. 

Every third plat is sown with a standard and 
uniform lot of seed grown on the University 



TIMOTHY-BREEDING AT CORNELL. 



271 



farm, and in 1905 all new check plats were sown 
with seed from one plant. The check plats meas- 
ure any variation in soil conditions, and each 




Fig. J. — A timothy plant that runs almost wholly to leaf. 

variety or sample is measured by the yield or 
stand of the check plat alongside. 

Example : — 

Plats. 123456789 10 

c c c c 

It was soon apparent that the widest variations 



272 CURRENT PLANT-BREEDING PRACTICE. 

would be developed in the plants. These varia- 
tions are of the following kinds : — 

(«) In duration : some annual, others perennial ; 

(6) In stooling power : some ten heads, others 
two hundred and fifty ; some have longer stolons 
than others ; 

(js) In time and manner of bloom : some a 
week or ten days earlier than others ; 

(d^) In character of leaf : some are long, others 
short ; broad, narrow ; smooth, rough ; erect, 
spreading ; 

(#) In shape and size of head and seed-produc- 
tion : large, thick heads can carry plenty of seed ; 
some plants that promised well for pasture had 
very poor heads and little seed ; 

(/) In character of culm : some erect, others 
spreading ; 

(#) In general time of maturity : some develop 
early and by August will have a second lot of 
heads in bloom ; others will not ; 

(K) In character of inflorescence : panicled and 
not ; 

(J) In vigor : in 1904, out of 9114 plants set in 
fall of 1903 from American-grown seed, 37 per 
cent were dead in 8 months, and 40.5 per cent in 
the first year. By 1905, or nearly 2 years after 
planting, 49.4 per cent had succumbed. 

0') In yield: in 1904, of the 5619 survivors 
above-mentioned, 103 yielded between ^ and J 




Fig. K. — A timothy plant that runs much to seed. 



274 CURRENT PLANT-BREEDING PRACTICE. 

pound hay and 3 yielded half a pound; 5500 
yielded less than -J pound. In 1905, of the 4612 
survivors, 4 yielded over 1^ pounds of hay and 48 
over one pound. 

In Figs. H to L are shown some of the kinds 
of variation or differences in timothy plants. 

Of course, nearly all the plants turned out to 
have no superior merits. In 1905, plants had 
been grown from seeds of ninety-three selected 
plants and three varieties were secured — enough 
for ninety-six plats. The characters were such as : 
heavy yield, poor yield ; coarse stem, fine stem ; 
early in bloom, late in bloom ; thin heads, thick 
heads; broad leaves, narrow leaves; tall; leafy, 
not leafy ; etc. All of these plats are checked by 
having a check plat beside them. All check plats 
are sown with seed from one plant, No. 9.03, 
the heaviest yielding plant having two years' 
record. In addition, centgener plats (containing 
one hundred plants placed in ten rows of ten 
each, six inches apart) were set from the thirteen 
heaviest-yielding plants. These are checked with 
No. 9.03 plants and have five foot alleyways be- 
tween, to permit of covering the plat with canvas 
to prevent cross-pollination. Thus far the prog- 
eny from three heavy-yielding plants selected 
in 1904 have transmitted heav}^-yielding charac- 
ters, and the progeny of weak plants are weak 
and small in size. 




Fig. L. — A productive timothy plant. 



276 CURRENT PLANT-BREEDING PRACTICE. 

IV. United States Department of Agri- 
culture. 

Probably the largest organized governmental 
plant-breeding enterprise in the world is in the 
United States Department of Agriculture. The 
" Laboratory of Plant-Breeding " is in charge of 
Dr. H. J. Webber, himself an expert breeder. 
Aside from the cotton-breeding, citrus-breeding, 
and other investigations by Dr. Webber, the fol- 
lowing work was going forward in 1905 : — 

Alkali and Arid Plant-Breeding, Thos. H. Kearney and L. 

L. Harter. 
Tobacco-Breeding, A. D. Shamel, W. W. Cobey, and Dr. W. 

W. Garner. 
Corn-Breeding, C. P. Hartley and E. B. Brown. 
Cotton-Breeding, Dr. D. N. Shoemaker, Prof. D. A. Saunders, 

E. B. Boykin, Prof. A. W. Bennett, Prof. S. M. Bain, and 

H. A. Allard. 
Oat- and Potato-Breeding, J. B. Norton. 
Wheat-Breeding, M. A. Carleton. 
Breeding of Disease-resistant Cottons, Watermelons, Cow 

peas, etc., W. A. Orton. 
Sugar-Beet-Breeding, Dr. C O. Townsend. 

Aside from the above principal lines of work, investiga- 
tions are being conducted by the Department in the breeding 
of carnations, roses, dahlias, lettuce, apples, pears, and other 
plants. 

In order to explain the point of view and to 
exhibit the methods of the work of this labo- 
ratory, I have secured from Dr. Webber and Mr. 
Carleton brief summaries of some of the pieces of 
work ; and these statements comprise the remain- 
der of this chapter. 




Fig. M. — Citranges (Hybrids of orange and Citrus trifoliata) . Top 
fruit Citrus trifoliata. Top pair, Rusk Citrange. Bottom pair, 
Willits Citrange. g nat. size. Reduced from colored figures 
in Yearbook of tbe Department of Agriculture. 



278 CURRENT PLANT-BREEDING PRACTICE. 

Citrus-breeding, 
By Herbert J. Webber. 

Work on the production of frost-proof types was 
started first in 1893-1894, but the hybrids were lost 
by accident ; other hybrids were made in 1896 and 
1897. A study of the possibilities in this direction 
indicated clearly that if any great advance was to 
be made, it would probably come through hybridi- 
zation. For very many years, growers had been 
carefully watching for hardy variations, and among 
the many thousands of seedlings grown in Florida 
and other countries where freezes occur occasion- 
ally, such hardy variations, if there were any, would 
have been noticed and utilized. The Department 
sought to produce hardy types by combining the 
hardy but worthless trifoliata orange (Citrus tri- 
foliata) with the common sweet orange, hoping to 
secure hybrids having the hardiness of the trifoliata 
and the edible fruits of the common orange. 

The hybrids were found to vary greatly in the 
first generation, all that have thus far fruited pro- 
ducing markedly different types of fruit. The 
majority of these, as would be expected, have pro- n 
cluced worthless sorts. The two sorts crossed 
were very distinct species and it was expected that 
a second generation of the hybrids would have to 
be obtained in order to secure the necessary varia- 
tions ; fortunately, however, the variation in the 



CITRANGES. 279 

first generation was sufficient to give opportunity 
for selection. Three hybrid seedlings have already 
fruited which produce fruits of undoubted value, 
and these have been named and distributed to 
growers. These three new hardy fruits form a 
distinct new class of citrus fruits, and have been 
named Citranges (Fig. M). The three varieties 
or clons have been named respectively the Rusk, 
Willits, and Morton. The Rusk, which is a 
hybrid of orange 9 x trifoliata $ , is a beautiful 
little fruit resembling a tangerine orange in color 
and appearance, being nearly round and reaching a 
maximum diameter of about two inches. It is 
nearly seedless, averaging about one seed to two 
fruits. The pulp is exceptionally juicy and rather 
sour to eat out of hand without sugar. It is 
slightly bitter but not more so than the pomelo ; 
with sugar it is a refreshing fruit to eat out of 
hand. It makes a very delightful citrangeade, a 
good pie, and excellent marmalade and preserves. 
For the latter uses it may ultimately be grown 
extensively. 

The Willits, which is a hybrid of trifoliata 9 
X orange $ , is very similar to a lemon, though 
differing in appearance. It has a rough, ribbed 
surface, but nevertheless a fairly thin skin and is 
very, juicy. In cross-section it resembles the finest 
lemons. The fruits of the Willits make an excel- 
lent citrangeade of high quality and can be used 



280 CURRENT PLANT-BREEDING PRACTICE. 

for culinary purposes when the lemon is now used. 
Served with fish or ice tea, they will not be distin- 
guished from the lemon unless well known to the 
eater. 

The Morton, which is a hybrid of trifoliata 9 x 
orange $ , produces a fruit as large as the ordi- 
nary orange, and so similar in appearance to the 
orange that it can hardly be distinguished as a 
distinct fruit. It is almost totally seedless and is 
sweeter and less bitter than either the Rusk or 
the Willits. With sugar this variety is a very 
fair dessert fruit and is to be recommended mainly 
for use as a breakfast fruit. It is very near to a 
sweet orange. 

Young trees of these three fruits have endured a 
temperature of eight degrees above zero, and it is 
believed that by slight protection for one or two 
winters, while the trees are young, they may be 
grown throughout South Carolina, Georgia, Ala- 
bama, Mississippi, Louisiana, in the greater part of 
Texas, in southern Tennessee and Arkansas, and 
in regions of low altitude in New Mexico, Arizona, 
Oregon, Washington, and northern California. In 
none of the above regions, except southern Lou- 
isiana and Arizona, can the ordinary orange be 
successfully grown. The citrange will thus 
extend the region of citrus culture about four 
hundred miles north of the present citrus belt. 

The Production of New and Odd Types. — There 



TANGELOS. 281 

is a continuous demand for new and odd varieties 
of citrus fruits and crosses were made of many 
different types of fruits. Hybrids of the tanger- 
ine and pomelo have given rise to a new group 
of fruits which has been designated the Tangelo. 
One variety of tangelo has already been named 
the Sampson (Fig. N), and another still under 
test will probably be named and distributed next 
year. The tangelo produces a fruit intermediate 
between the tangerine and pomelo, having the 
loose, " kid-glove" skin of the tangerine. It is 
sweeter than the pomelo, but more sprightly acid 
than the tangerine. The characteristic bitter 
flavor of the pomelo is considerably reduced but 
remains as a pleasant suggestion of that popular 
fruit. Withal the tangelo is an excellent dessert 
fruit and an interesting and valuable acquisition. 

Two new tangerines, the Weshart and Trimble, 
resulting from a hybrid of Dancy Tangerine with 
Parson Brown Orange, have been named and dis- 
tributed. While resulting from carefully hand- 
crossed seed, these fruits are strictly tangerines in 
all qualities. They differ from the ordinary va- 
rieties in being larger and about two weeks earlier 
in season — two characters of value. 

A good blood orange has resulted from a cross 
of ordinary orange with pomelo, neither parent 
showing in any degree the " blood " character. 

Two new limes have been named, which resulted 




Fis. N. — Sampson tangelo. f nat. size. Adapted from Yearbook. 



PINEAPPLES. 283 

from carefully hybridized seed of West Indian 
lime 9 with the Sicily lemon $ . Both are true 
limes in every noticeable quality, one producing 
a small fruit and the other a large fruit. Only a 
small number of the hybrids under test have yet 
fruited, and many more interesting new sorts will 
doubtless be obtained. 

Pineapple-breeding. 

By Herbert J. Webber. 

The common market pineapple is ordinarily 
entirely seedless. So rarely are seeds formed that 
few people even among the growers have ever 
seen them. By hand-crossing different varieties 
it was found possible to secure a fairly large 
proportion of perfect seeds. From crosses of 
different varieties made by the writer in conjunc- 
tion with Mr. W. T. Swingle, about three hundred 
hybrid seedlings were obtained. From such a 
small number of seedlings ordinarily very little of 
value would be expected to result. As a matter 
of fact, nearly twenty of these seedlings are quite 
different from existing varieties and seem to pos- 
sess sufficient merit to justify their being named 
and. distributed. The exceptional good quality 
and flavor of the hybrids as a whole is very 
noteworthy. It would seem as though the quality 
of the ordinary varieties must have deteriorated 
under long vegetative propagation and require 



281 CURRENT PLANT-BREEDING PRACTICE. 



the rejuvenescence of cross-fertilization to restore 
their good qualities. Unless some such explana- 
tion be true, it is difficult to understand the 
uniformly superior quality and flavor of the 
hybrids. Only one smooth-leaved variety is now 
cultivated in this country, the Smooth Cayenne, 
and this was crossed with various sorts with the 
hope of producing more smooth-leaved varieties. 
Such hybrids have furnished a number of promis- 
ing smooth-leaved varieties. It is interesting to 
note, however, that almost as many smooth-leaved 
seedlings resulted from crossing spiny leaved 
sorts as resulted when the Smooth Cayenne was 
used as one parent. Five of these hybrid seed- 
lings which have been fruiting since 1901 will 
be described in the 1905 Yearbook of the Depart- 
ment of Agriculture. 

Cotton-breeding. 

By Herbert J. Webber. 

Production of Long-staple Upland Races. 

The cotton-breeding work of the Department 
was started in 1899, when the writer first took up 
the problem of creating better-yielding, long-staple 
races. There is a growing demand for long-staple 
cotton, and the regions where the long fibre can 
be profitably cultivated are very limited. The 
short-staple sorts, having fibre usually from seven 






COTTON. 285 

eighths to one and one-sixteenth inches in length, 
are grown all over the great cotton belt of the 
United States. Of this cotton we produced last year 
(1904) over thirteen million 500-pound bales, while 
the maximum production of long-staple upland 
sorts, grown principally in the rich bottom lands 
of Mississippi and Louisiana, has never exceeded 
about two hundred thousand bales per annum. 
The long-staple upland cottons produce fibre 
ranging from one and one-fourth to one and one- 
half inches in length, and usually sell from 
twelve to eighteen cents per pound when ordinary 
cotton is selling at nine and ten cents. The longer 
the fibre the better and stronger the yarn pro- 
duced, and the better the goods manufactured. 
If, then, we can secure one and one-fourth to one 
and one-half inch staple cotton that will equal in 
yield the ordinary upland cotton on the same soils, 
the longer-stapled sorts should ultimately sup- 
plant the short-staples. 

It seemed to the writer that the most feasible 
way of producing such long-staple sorts adapted 
to upland regions was to hybridize the very long- 
staple sea-island cotton (G-ossypium Barbadense) 
with the short-staple upland sorts (G-ossypium 
hirsutum) and select the hybrids in an upland 
cotton region, the aim in such an experiment 
being to combine the fine, long, and strong lint 
qualities of the sea-island cotton with the large, 







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288 CURRENT PLANT-BREEDING PRACTICE. 

round, easy-picking bolls, greater productiveness, 
and adaptability to upland conditions of the 
upland short-staple cotton. Another feature 
that seemed important to the writer was to get 
in the hybrid varieties, the smooth black seed of 
the sea-island instead of the fuzzy seed of the 
upland, so that roller gins could be used in gin- 
ning the cotton, if found desirable. Throughout 
the work these ideals have been kept closely in 
mind, and every plant examined carefully, and 
those selected, carefully graded. 

In 1899 a number of hybrids were made and 
the first generation was grown in 1900. These 
were examined and the most promising bred 
inter se. In 1901 six acres of second-generation 
hybrids were grown, thus giving many thousand 
plants to select from. In this generation twelve 
specially good plants possessing the desired com- 
bination of characters were selected and each of 
these were planted in isolated acre patches in 
1902. A large number of other plants were also 
selected and grown together in a miscellaneous 
patch the next year. In 1902 the progeny of each 
of these acre patches was carefully watched, and 
every undesirable type pulled out as soon as dis- 
covered, reducing the number of plants in each 
acre to about twenty -five or thirty. These were 
used to plant the same isolated patch the next 
season (1903). This process, coupled with careful 



COTTON. 289 

grading, has been continued every year since. By 
the fifth generation (190-1) the twelve types had 
been reduced to five, and these had reached a 
stage of fixity as complete as is found in the ma- 
jority of cotton races ; they yet produced a good 
many plants with fuzzy seeds and some with short 
lint. This year (1905, in the sixth generation) 
one of the varieties has reached sufficient fixity 
and is of such promise that it is thought to be 
ready for introduction into cultivation as soon as 
it can be propagated in quantity. Considerable 
roguing will be necessary to keep it up to a high 
state of production and quality. Two other of 
the hybrid types are also nearly fixed and will cer- 
tainly be valuable sorts. One of these hybrids, 
it is believed, will give lint nearly equal to the 
fine sea-island in length, strength, and fineness. 
The lint, however, is produced on a typical up- 
land cotton plant with large, round bolls. The 
fields of these cottons this year at Columbia, S.C., 
are equal to the best uplands in the vicinity, 
where unselect seed has been used. (Figs. O and 
P show short-staple and long-staple cottons.) 

The greatest surprise in our work has come 
through experiments in the improvement of the 
lint by the straight selection of certain big-boll 
uplands. A three-year selection from Jones Im- 
proved ordinarily having lint averaging one inch, 
and not over one and one-eighth, has given us this 



290 CURRENT PLANT-BREEDING PRACTICE. 

year a field of seven acres averaging about one 
and one-fourth inches, and several progenies from 
selection of last year averaged one and three- 
eighths inches of fine, long, strong cotton. It is 
exceedingly promising and will be grown for dis- 
tribution next year. These plants have been 
carefully selected, the pedigree running back to 
carefully selected individuals three generations 
ago. 

A straight selection of Russell Big Boll now in 
fourth generation of selection is also showing the 
same marvellous increase in lint length without 
reduction of its productiveness. If these cottons 
will hold up three years after selection ceases, they 
should drive short staples out of the market ulti- 
mately. I believe that the continuation of the 
selection will render the character practically fixed 
until reduced by intermixing. 

We have a pedigreed strain of a short-staple 
variety, Pride of Georgia, which has this year and 
last given a very much better yield than ordinary 
cotton. We expect to send seed of this to about 
three thousand planters this winter (1905-6). 

Many other selections and hybrids are under 
experimentation, some of which will doubtless 
prove valuable. 



BREEDING OF WHEAT. 291 

Wheat-breeding. 
By M. A. Carleton. 

In the wheat-breeding experiments of the United 
States Department of Agriculture there are about 
950 wheat hybrids, selected from 286 original 
crosses. The accompanying illustrations (Figs. 
Q-T) are very good examples, showing some of 
the most interesting variations. A brief descrip- 
tion is given of the methods of operation, followed 
by some notes on results. 

Method of Work. 

A very large part of the work of improving 
wheat is simply the selection each year of better 
plants and the occasional introduction of distinct 
varieties from foreign countries that are better 
adapted to the particular conditions under which 
the crop is to be grown. We have found, indeed, 
that if this kind of work is conducted thoroughly, 
with a broad knowledge of wheat varieties and 
their adaptation, the results of hybridization are 
made much more effective and, especially, very 
much time is saved. We are obliged to infer 
from previous experience that much work in 
wheat-breeding has been done needlessly because 
of the lack of previous knowledge of varieties, 
which knowledge would have shown that there 
already exist certain varieties much better than 
those obtained through cross-fertilization. To 



292 CURRENT PLANT-BREEDING PRACTICE. 

illustrate, if one wishes to secure varieties more 
resistant to rust, there will be a saving of both 
time and labor by securing first the variety best 
in this regard among those already in cultivation. 
Such varieties as are best with respect to any one 
quality are often found in foreign countries. 

The best varieties, so far as we know them, 
having been established by thorough adaptation 
tests, are used from which to select the best plants 
for use in cross-breeding. Suppose we wish to 
improve the wheat of the Middle West, generally 
represented by the Crimean or Turkey winter 
wheat, by giving it greater rust resistance. The 
best plant of the Crimean as to yield, hardiness, 
and quality of grain is selected and crossed with 
the best plant of a variety of the durum wheat 
group, the Velvet Don, for example, which has the 
quality of rust resistance to an exceptional degree. 
This latter variety is also very resistant to drought. 
We hope, therefore, to secure from the progeny a 
new variety having all the good qualities of these 
two parents, and will try, as far as possible, to 
eliminate the bad qualities. The good qualities 
are yield, winter hardiness, excellence of kernel 
for bread-making, rust resistance, and resistance 
to drought. 

The parent plants having been selected, it will 
depend on the circumstances of flowering as to 
which one will be chosen as the female parent. 



POLLINATING WHEAT. 293 

The Velvet Don being for most regions a spring 
variety, it would be chosen in this case for the 
female parent, as its time of flowering would be 
a little later than that of the Crimean, and we can 
therefore be more certain that it has not been self- 
fertilized. 

The operation of artificial cross-pollination is 
about as follows : The articles provided for the 
work are, a small pair of forceps, such as used in 
ordinary laboratory work, a small pair of curved 
scissors (similar to manicure scissors), and a 
supply of very small white tags with strings at- 
tached ready for use. With the forceps the glumes 
of the flower to be cross-pollinated are spread apart 
and the three stamens taken out bodily, thus com- 
pletely emasculating the flower if the operation 
has been done at the proper time, just before the 
anthers are ripe. 

The same day or the next morning, pollen is 
taken from the fully ripened flowers of the plant 
selected for the male parent and scattered within 
the opened glumes of the flowers that were emas- 
culated as above described, after which the glumes 
are smoothed back into their former positions as 
nearly as possible. There appears to be much 
variation in the practice of different persons as to 
the number of flowers pollinated. On an average, 
we cross-pollinate about sixteen flowers in each 
head operated on, these being the eight outside 



294 CURRENT PLANT-BREEDING PRACTICE. 

flowers of the four best spikelets on each side of 
the head. The spikelets are chosen just above 
the middle of the head, that is, a little nearer 
to the apex than to the base. In all cases where 
there are more than two flowers to each spikelet, 
the middle one and any others that may be present 
are also emasculated, but not pollinated, the outside 
flowers usually producing a little the best grains. 
The spikelet immediately above those that are 
pollinated and the one immediately below are 
nipped with the scissors, which mark indicates 
that the operation has been made on the spikelets 
between. After the operation is performed, one of 
the white tags is tied to the stalk and the names 
of the parents and the date of the cross written 
upon it. So far as can be determined, the best 
head of the plant is pollinated, but sometimes two 
or three heads of the same plant are employed. 
After trying the experiment for some time, the 
practice of tying paper or cloth bags over the 
cross-pollinated heads has been abandoned. Often 
the head is much injured by the operation, particu- 
larly in times of wet weather, and there does not 
seem to be much need of it. After some experi- 
ence one can determine very readily whether there 
has been any natural cross-pollination other than 
the one intended simply from the nature of the 
results, and really such an instance seems never to 
have occurred in our experience. In this connec- 



CROSSING WHEAT. 295 

tion it is worth while to remark that one becomes 
able after a while to determine rather accurately 
what parents were employed in any particular 
cross merely by the characters of the progeny. 

At first there are likely to be many failures in 
the production of kernels from these cross-pollina- 
tions, but after considerable experience ordinarily 
good work will result in an average production 
of kernels from about sixty per cent of the crosses. 
One great mistake often made, and one that was 
made by ourselves at the beginning of our Avork, 
is that of cross-pollinating too small a number of 
flowers. Instead of eight or a dozen cross-pollina- 
tions, there ought to be more nearly one hundred 
in the case of every cross. It may be necessary to 
secure a great many variations and to have a large 
number of progeny before there is obtained the 
particular variation that one desires. In all our 
operations now, we are attempting to produce in 
every case just as many cross-pollinated kernels 
as possible up to the limit of about one hundred, 
but we always expect later to discard scores of 
plants from the progeny. It is only by having a 
large number of individuals to work on and by 
a process of rigid elimination that we are able to 
secure the best results. 

Another way by which a number of undesirable 
plants are eliminated, particularly in the winter- 
wheat region, is the practice of planting the 



296 CURRENT PLANT-BREEDING PRACTICE. 

kernels produced from these cross-pollinations in 
exactly the same way and under the same condi- 
tions as the ordinary standard wheats are planted. 
It is not the practice in our work to give any 
special care to these new plants. Therefore, only 
the hardiest survive, and in some cases as small 
a number as ten per cent of the entire number 
planted has survived the winter. The method of 
planting the seeds of our hybrids, as well as the 
standard varieties of all the cereals, is to sow them 
in drill rows about fifteen inches apart. In the 
cases of the standard varieties, the furrow is first 
made and then the seed sown by a hand drill in 
the furrow thus prepared. Of course in the cases 
of the hybrids the seed must be sown by hand. 
Later on, in order that the hybrids may be grown 
under ordinary field conditions and yet that statis- 
tical results from the progeny may be obtained, 
the seeding of each one is duplicated in two ways : 
that is, a small part of the seed is sown, a ker- 
nel, in a place about six inches apart, in a row 
twenty feet long, the remainder of the seed being 
sown with a hand drill just as the standard wheats 
are planted. 

The work requiring the most care is the after- 
treatment and selection of these hybrid wheats. 
As stated, scores, and later on hundreds, of 
individual plants from the progeny of each 
hybrid are discarded every year; but of course it 



WHEAT RECORDS. 297 

requires constant study and rather critical judg- 
ment to determine whether it is wise to discard 
a plant or not. Also, because our experimental 
stations are at a number of different points 
throughout the country, it is often true that a line 
of variation in the progeny, though found to be 
ill adapted to a certain locality, may be very 
nearly just what is wanted in some other district. 
Some of the most interesting work is that of the 
separation of the progeny of these hybrids into 
classes, based on the lines of variation having 
qualities suited for different purposes or regions. 
A complete pedigree record is kept of all the 
progeny of the original hybrid, and later, when 
the new varieties that have been developed along 
certain lines of variation become fixed, a summary of 
the statistical results shown in the notes on these 
progeny is made out on large sheets. Detailed 
notes on the characteristics of the individual plants 
are recorded in a field note-book made of a size 
conveniently to fit the coat pocket. In the case of 
the standard varieties, they are all entered in this 
note-book according to accession number, a list 
of the varieties corresponding to the numbers 
being placed in the back part of the book for 
reference when needed. After the column of 
numbers there are many other columns in which 
there is given opposite to each number the notes 
on height of plant, time of ripening, rust resist- 



298 CURRENT PLANT-BREEDING PRACTICE. 

ance, size and shape of heads, character of the 
kernels, etc. After fixation, each hybrid is given 
an accession number and treated the same as 
a standard variety. Before fixation, and while the 
variations among the progeny are under observa- 
tion, the different variations are indicated by a 
special system of numbering, which is the same as 
that used also by Dr. H. J. Webber and his assist- 
ants in other plant-breeding work and which is as 
follows : The hypothetical cross of Velvet Don 
with the Crimean above mentioned, supposing the 
number of the cross to be twenty-three, would be 
indicated as follows, if the hybrid has been carried 
through the fifth generation, which is true now 
with nearly all of our hybrids : 23a 2-1-3-1-2. This 
number attached to a plant indicates that it is the 
second selection of plants of the fifth generation 
of the hybrid No. 23 Velvet Don x Crimean. 
After the first number, which is the number of the 
original cross, every figure indicates a generation, 
and therefore the number of figures show at once 
the number of generations in the cross. In this 
case the progeny has descended from the plant 
produced by the second grain in the cross, No. 
23a. From the seed of that plant a number of 
individuals are produced in the second generation, 
of which No. 1 was selected for this line of varia- 
tion. In the third generation No. 3 was selected. 
In the fourth generation No. 1 was selected, and 



WHEAT RECORDS. 299 

in the fifth, No. 2. The letter following after the 
cross number, which is a in this case coming just 
after No. 23, indicates which cross is referred to 
as regards the individual parent plants; that is, 
there might be another cross made of Velvet Don 
with Crimean, but in that case it would be No. 
23b, and if there were a third one it would be No. 
23c, the particular parent plants being different 
in the cases of b and c. In taking field notes 
on the hybrids, this number, 23a 2-1-3-1-2, is 
placed in the proper column instead of the ac- 
cession number, as in the case of the standard 
varieties. 

Results. 

Although we have experimented with many 
hybrids, it is desirable, for the purpose of conden- 
sation, to illustrate the results simply in a general 
way by a description of a few of the most repre- 
sentative cases. The accompanying photographs 
illustrate four of the hybrids here described, all 
the pictures being similarly reduced in size. Al- 
though the hybrids have been carried through five 
generations, it is impossible, without much further 
work, to discuss here the variations farther than 
the third generation. However, this includes 
the most interesting periods, there being very 
few changes that are of interest in the later 
generations. 



300 CURRENT PLANT-BREEDING PRACTICE. 

In some cases it would be desirable to show the 
kernels, but in most instances these are not avail- 
able and at any rate could not very well be shown 
in a photograph. In mentioning a hybrid, the 
name of the female parent is given hrst, then the 
sign x , followed by the name of the male parent. 
In the accompanying photographs the parents are 
shown at the left of the sheet, the first one being 
the female parent. 

Special Notes on Certain Crosses. 

I. Hybrid T#xl344. — Yx, the female parent, 
is a hardy, red-chaffed, red-grained, bearded winter 
variety, and 1344 is a white velvet-chaffed variety 
with rather soft grains and no beards. In the 
second generation, plants with both red-chaffed 
and white-chaffed heads appear, the most interest- 
ing and valuable of which are those having large, 
vigorous heads with red chaff, the size and vigor 
coming from the male parent and the hardy char- 
acteristics and good quality of the grain from the 
variety Yx. 

II. In a cross of Ghirka Winter x 1392, there 
is introduced the interesting feature of a bearded 
club wheat in the second parent. In the first 
generation, one plant is clubbed but has no beards. 
In the second generation there are two individuals 
with clubbed heads and no beards, and one other 
with clubbed heads and beards. The parent 1392, 



WHEAT CROSSES. 



301 



coming originally from north central Asia, is char- 
acterized by early maturity, and this characteristic 
appears in several of the progeny. Earliness in a 
plant something like No. 1 or 2 of the second 
generation (see illustration) would be very im- 




Fig. Q. — Ghirka Winter x 1392. 1. Female parent. 2. Male parent. 
3. First generation. 4. Second generation. 

portant from an economical standpoint. Ghirka 
Winter is a very hardy winter variety with hard, 
red grains, white chaff, and no beards. (Fig. Q.) 
III. One of the interesting crosses is that of 
Arnautka x 1403. Arnautka is the native durum 
wheat of the Northwestern States; that is, it has 
been grown there in a small way for a quarter of 



302 CURRENT PLANT-BREEDING PRACTICE. 

a century, having come originally from Russia. 
The 1403 is also a durum variety, but differs from 
the Arnautka in having a velvet chaff. In this 
cross there is an unusual and interesting feature 
of a true club wheat appearing in the second 
generation which is also bearded. Neither of the 
parents is known to be a hybrid, so it is not 
likely that this plant could be a reversion to an 
older ancestor. 

IV. Grhirka Winter x Spelt. In this cross 
there is introduced as the male variety a repre- 
sentative of a distinct group of wheats, the true 
spelt. These wheats are not grown at present in 
this country except at the experiment stations, 
although the name is often incorrectly applied to 
emmer. The parent, Ghirka Winter, has already 
been described. The spelts have long, slender 
heads with usually only two grains in a spikelet 
and the spikelets arranged far apart, producing a 
very loose head. For the first generation of this 
cross, only one plant is represented in the illustra- 
tion, and this is in all essential features like the 
male parent. In the second generation some of the 
progeny approach the male parent by different de- 
grees, Nos. 3 and 5 (see illustration) being very 
much like it. The spelts are very constant in 
fertility, every flower almost always producing a 
grain, and this characteristic, if transmitted to the 
offspring of a cross, is of economic value. They 



WHEAT CROSSES. 



303 



also have a very tenacious chaff. Nos. 2 and 4 
are likely to be of the greatest economic value, 
having to some extent the good qualities of both 
parents. (Fig. R.) 

V. In the cross of Diehl Mediterranean x 




Fig. R. — Ghirka Winter x Spelt. 1. Female parent. 2. Male 
parent. 3. First generation. 4. Second generation. 

Jones's Winter Fife, there are illustrated varia- 
tions to the third generation. The female parent 
is a red-chaffed, bearded wheat without velvet. 
The male parent, Jones's Winter Fife, is a beard- 
less, white, velvet-chaffed wheat. In the third 
generation it will be seen that there is quite a 
range of variation, although all of the plants were 



304 CURRENT PLANT-BREEDING PRACTICE. 



produced from the single plant here shown of the 
second generation. (Fig. S.) 

VI. Jones's Winter Fife x Ufa emmer. In 
this cross several very interesting things are 
shown. One soon finds that the emmers stamp 




Fig. S. — Diehl Mediterranean x Jones's Winter Fife. 1. Female 
parent. 2. Male parent. 3. First generation. 4. Second gen- 
eration. 5. Third generation ; five plants, progeny of No. 4. 

their characteristics very emphatically upon the 
offspring in any cross in which they occur. At 
the same time Jones's Winter Fife is itself a very 
vigorous hybrid with a long pedigree, and is also 
quite pre-potent. In the first generation, No. 1 
(see illustration), is very much like the female 
parent, Jones's Winter Fife, having even the 



WHEAT CROSSES. 305 

velvet chaff, which is a characteristic of that 
variety. No. 2, however, is a very striking ex- 
ample in which the characters of both parents are 
distinctly shown, having a head of exactly the 
shape of the emmer and at the same time a thick 
velvet characteristic of the female parent. In 
this plant, however, there are no beards. In the 
second generation there is a club wheat with 
velvet chaff, which, however, is not shown in 
this illustration. To one not familiar with the 
history of either parent this fact would be pecul- 
iar, especially as neither parent is a club, and 
plants with clubbed heads, so far as we know, 
would not appear in crosses of one of the common 
wheats with an emmer unless one of the parents 
is itself clubbed. In this case the explanation, no 
doubt, is that several of the ancestors of Jones's 
Winter Fife were club wheats, so that this is a 
reversion to the character of an older ancestor. 
Even the plant of the second generation here 
shown (see illustration) is slightly clubbed, but 
otherwise has the shape of head and the beards 
of the emmer and the velvet chaff of Jones's 
Winter Fife. From this plant were produced 
all the variations shown in the four plants of the 
third generation here illustrated. (Fig. T.) 

VII. Finally, I would mention a cross of a red 
beardless spelt x Ufa emmer. The Ufa emmer 
is a rather hardy variety of this group, coming 



306 CURRENT PLANT-BREEDING PRACTICE. 

from extreme northeastern Russia near the 
Siberian border. In the progeny of this cross 
are a number of plants having heads very similar 
to those of our common wheats. The occurrence 
of these heads would indicate the possibility that 




Fig. T. — Jones's Winter Fife X Ufa emmer. 1. Female parent. 
2. Male parent. 3. First generation. 4. Second generation. 
5. Third generation ; four plants, progeny of No. 4. 

a number of our common varieties well known 
to-day originated many years ago from crosses of 
the spelts and emmers either with each other or 
with varieties of other groups. 



General Remarks. 

In our experiments we have succeeded in cross- 
ing all groups of wheats with the common 



REMARKS ON WHEAT CROSSING. 307 

varieties except the einkorn group, known botani- 
cally as Triticum monococcum. A number of at- 
tempts were made to cross with this group, but 
we are not certain so far that any one has suc- 
ceeded. However, several crosses have been 
made with the Polish wheat, which certain writers 
have supposed could not be accomplished. 

In all instances when a club wheat is one of 
the parents, there are striking variations, probably 
because of the fact that club varieties are almost 
always, or perhaps always, the direct result of a 
cross of two different wheat groups and not the 
result of a long series of selections. The hybrid 
would, therefore, naturally break up into many 
variations, showing a reversion to the characters 
of original ancestors. 

In many cases when one or both of the parents 
is already a hybrid, there are reversions to charac- 
ters of former ancestors which would be wholly 
inexplicable on any other basis than the fact that 
the parents themselves are hybrids. 

A spelt or an emmer, when used as one of the 
parents, invariably fixes emphatically its character- 
istics upon the progeny. 

It has been supposed that variations do not 
occur to any considerable extent in the first 
generation, but we have found some of our most 
striking variations appearing in this genera- 
tion, particularly in the case of crosses with 



308 CURRENT PLANT-BREEDING PRACTICE. 

fixed hybrids or with the emmer and club 
groups. 

Characters occasionally appear in the progeny 
which cannot be traced to either parent, and yet 
in cases in which neither parent is known to be a 
hybrid. 

Pedigree Records used in the Plant-breeding Work 
of the Department of Agriculture. 

By Herbert J. Webber. 

In all of the work of breeding pursued by this 
office, the individual parents are followed in prac- 
tically every case, unless it be pure selection work, 
where the following of the male parent is not very 
important. In all cases, however, the female 
parent is fully recorded and described. 

Numbering the plants. — The records in each 
crop are kept separate. Under each crop there 
is maintained a continuous series of what is 
termed " Series Numbers," or " Experiment Num- 
bers." For example, Series No. 1 may be hybrids 
of Constellation sea-island cotton, with pollen of 
Klondike Upland ; and all of the hybrids of this 
combination are placed under Series No. 1. Series 
No. 2 may be hybrids of Truitt with pollen of Texas 
Wood cotton ; and all of the hybrids of this com- 
bination will be placed under Series 2. Series 3 
may be a straight selection of Truitt, and all of 



PEDIGREE RECORDS. 309 

the selections of Truitt made under a given con- 
dition are given the No. 3. 

In the case of a hybrid, as in Series No. 1 
mentioned, a certain boll on a given plant may be 
crossed with pollen from one individual, while 
another boll on the same plant may be crossed 
with pollen from a different individual. It is 
thus necessary in keeping the record of the hybrids 
to have a method of designating each individual 
fruit or boll crossed. The different crossed bolls 
in this case would be numbered 1 A, 1 B, to 1 Z. 
The letters of the alphabet are usually sufficient 
to cover the number of crosses made of a certain 
kind. When the progeny of these different bolls 
are grown and the first generation of hybrids are 
produced, these hybrids are numbered as follows : 
The hybrids produced from capsule 1 A are num- 
bered 1 A 1, 1 A 2, 1 A 3, etc. Owing to the 
necessity of keeping the records within certain 
space, numbers are assigned only to those hybrids 
which are actually selected, so that in case of a 
large number of hybrids, only a few numbers 
would actually be preserved, although records 
would be preserved of the general variations in 
all of the hybrids produced. 

When a second generation is grown from the 
above first generation of hybrids, the individuals 
of the second generation would be numbered as 
follows : Those grown from 1 A 1 would be 



310 CURRENT PLANT-BREEDING PRACTICE. 

numbered 1 A 1-1, 1A1-2, 1 A 1-3, etc., and 
those from 1 A 2 would be 1 A 2-1, 1 A 2-2, 1 A 2-3, 
etc. 

This method illustrates the system of number- 
ing all hybrids in the third, fourth, and succeeding 
generations, the members of the different genera- 
tions being separated by a dash, as in the above 
instance, so that in the case of any combination a 
glance will show whether or not it is a hybrid and 
what generation the hybrid is in. In Series 2 
before indicated, the numbering Avould be in ac- 
cordance with the same rule, i.e. 2 A, 2 B, 2 C, etc., 
for the different crossed capsules, and 2 A 1, 2 A 2, 
2 A 3, and 2 B 1, 2 B 2, 2 B 3, etc., for the individual 
hybrids of the first generation. 

In the case of Series 3, which is a straight 
selection, there is not the necessity of using the 
letter, as the experiment starts with the selection 
of a certain number of individuals. The individ- 
uals which are first selected would thus be num- 
bered 3-1, 3-2, 3-3, 3-4, etc., the first number being 
the number of the series and the second number 
the number of the individual plants first selected. 
When these selections are grown in a second 
generation, they are designated as follows: 3-1-1, 
3-1-2, 3-1-3, and 3-2-1, 3-2-2, and 3-2-3, etc. It will 
be noticed by comparing Series 3 with Series 1 
and 2 that the numbers used for selections differ 
only from those used for hybrids in leaving out the 



PEDIGREE RECORDS. 311 

letter, which marks the individual capsules which 
are crossed in the case of Series 1. The use of this 
system of numbering allows the filing of record 
cards according to the series number and the 
number of the generation, so that they may be 
found with the greatest ease. 

Blanks used in keeping records. — The records of 
all hybrids and selections are made on loose sheets, 
which are filed either in books or in a card-index 
case. A special sheet is expected to be used for the 
record of each plant which is selected. The sheet 
has a blank form for the description of the plant and 
for the description of the progeny which it pro- 
duces. Plant-breeding Form No. 1 (sample on page 
315) is the introductory sheet to a series of hybrids. 
All introductory sheets are of thick paper and blue 
in color. The introductory sheets for selections 
are of similar form and color (see sample, page 316). 
On these introductory sheets is to be put, in the 
case of the hybrids, the description of the female 
and male varieties, and the object of the hybridiza- 
tion. In the case of selections, the description of 
the parent variety and object of the selection 
are recorded, together with any general notes on 
the plants which are grown for the selection. 

In the case of hybrids, a parental sheet is used, 
which corresponds to the letters used in designat- 
ing the different crosses. On this salmon-colored 
sheet (see sample, page 317) is given the descrip- 



312 CURRENT PLANT-BREEDING PRACTICE. 

tions of the individual characters of the female 
parent and the individual characters of the male 
parent, together with notes on the general progeny 
grown from a certain boll or fruit. In the case of 
selections there is no parental sheet used as the 
different bolls and fruits are not kept separate. 
When the individuals are grown and notes made 
on them, individual white sheets are used, both in 
the case of selections and hybrids. One of these 
sheets for hybrids is illustrated in P. B. Form 3 
(page 318), which is a blank that can be used with 
hybrids of any plants, and is not specially adapted 
to any particular crop. The same individual 
white sheet for selections is illustrated in P. B. 
Form 7 (page 319). 

Whenever much work is to be done with a cer- 
tain crop, it becomes necessary to have the blanks 
drawn up in the form of score cards, in order that 
the important characters of the breeding material 
may be scored according to a statistical method. 
Such cards for cotton hybrids are illustrated in 
P. B. Forms 4 (salmon) and 5a (white) and P. 
B. Forms 8 (blue) and 9a (white) for cotton 
selections. In all of the work a regular score 
card is used ; on page 328 is shown a blank yellow 
score card which is used in cotton-breeding work 
(P. B. Form 15). The valuation of the different 
points is filled in according to the particular ideal 
which the breeding is expected to develop. 



KEEPING RECORDS. 313 

The record sheets, as mentioned above, are the 
uniform size of nine and one-quarter inches long by 
seven inches in width, and may be filed in any loose 
file sheet. The best form which has been found for 
this purpose and the one which is used in the 
Department's work is the so-called " Perfect File," 
which holds the sheets firmly and at the same 
time allows of a single sheet being extracted at 
any point without disarranging the others. 

A difficulty with the above plan has been found 
in the fact that the record sheets are too large to 
carry in the field, and more recently a small sheet 
of the standard size of six and one-half inches long 
by four inches wide has been used. These sheets 
are bound in note-books, so that they may be torn 
out and filed in card -index cases. 

The different blank forms on the smaller sheets 
are arranged exactly the same as in the case of the 
larger ones described above. P. B. Forms 41, 42, 
and 46 show the general forms which are used in 
making the records in cotton selections (pages 330 
to 332). Number 41 is white, 42 pink, and 46 blue. 
It will be seen on P. B. Form 41 (page 330) that 
the important characters which are to be judged 
are placed on a score card in the upper part of the 
sheet ; as, for example, under " Season," if a plant 
is early, one would check the word " early " ; and 
if a cotton which is early is scored on the basis of 
ten points the score record of probably eight points 



314 CURRENT PLANT-BREEDING PRACTICE. 

would be inserted on the blank just below " Sea- 
son." In the space marked "Length of Lint," 
one would insert the exact measurement of the 
lint, as, for instance, one and one-quarter inches, 
and below this point in the score line insert the 
score value for this length of lint. These smaller 
sheets which are put up in pocket note-books are 
very much handier to use than the larger sheets ; 
and so far as we can find, answer every purpose. 
We are rinding it necessary continuously to 
reduce the amount of notes taken, rather than 
increase them. One is inclined to get a large 
collection of notes, and if he is doing extensive 
work is never able to correlate or utilize them. 
One of the most important things for the breeder 
to do is to learn to limit the notes to the factors of 
importance, and avoid making notes or saving 
plants indiscriminately. 

[The forms reproduced on pages 315 to 319 are 
necessarily shortened as to horizontal length in 
order to accommodate them on a single page.] 



Hybrid. 



Introductory 
Sheet. 



Series No. 

Female Parent , U.S.P.B. No. 

Male Parent , U.S.P.B. No. 

Notes , page Year 

Experimenter 

Characters of Female Variety : 



P. B. Form 1. 



Characters of Male Variety : 



Object of Hybridization : 



Introductory hybrid record sheet. Blue. 9\ x 7 in. 
(P. B. Form 1.) 

315 



Selection. 



Introductory 
Sheet. 



Series No. 

Parent Variety , U. S. P. B. No. 

Notes , page Year 

Experimenter 

Character of Parent Variety : 



P. B. Form 6. 



Object of the Selection ; 



Notes on Plants grown for Selection 
(See Notes , page ): 



Introductory selection sheet. Blue. 9£ x 7 in. 
(P. B. Form 6.) 



316 



Hybrid. 
Parental Sheet. 



Hybrids, Series No. 

Female Parent , U. S. P. B. No. 

Male Parent , U. S. P. B. No. 

Notes , page Year 

Experimenter 

Individual Characters of Female Parent : 



P. B. Form 2. 



Individual Characters of Male Parent 



Progeny Notes (See Notes , page ): 



Parental sheet. Salmon. 9|x7 in. (P. B. Form 2.) 

317 



Hybrid. 

Individual 

Sheet. 



Parentage 

Inbred Year 

Experimenter.. 



Hybrid No.... 

?, x $ 



P. B. Form 3. 



Field Notes (See Notes , page ) 



General Notes 



Progeny Notes (See Notes , page ): 



Individual hybrid sheet. White. 9^x7 in. (P. B. Form 3.) 

318 



Selection. 

Individual 
Sheet. 



Selection No. 

Parent Variety , U. S. P. B. No. 

Inbred Year 

Experimenter 



P. B. Form T. 



Field Notes (See Notes , page ): 



General Notes 



Progeny Notes (See Notes , page ); 



Individual selection sheet. White. 9^x7 in. (P. B. Form 7.) 



319 



Tot ton Hybrid. 
Parental Sheet. 



P. B. Form 4. 



Female Parent 

Male Parent 

Notes , page Year Experimenter. 



Cotton Hybrids, Series No. 

, U.S.P.B. No. 

, U.S.P.B. No. 



Individual Characters of Female Parent: 



Individual Characters of Male Parent: 



Progeny Notes (See Notes , page ): 



Locality 
Where 
Grown 



Date 
Planted 



Number 
Plants 
Grown 



Number 
Plants 
Har- 
vested. 



Easi- 
ness 



Beight 

Form 

of 
Plant 



Disease 

Resist- 
ance 



Size of 
Bolls 



Open 
ingof 
Bolls 



Seed 



Size 



Per 

cent 

Smooth 



Per 

cent 

Tufted 



Lint 



Length 



Color 



Fine- 
ness 



Uni- 
form- 
ity 



Strength 



Dnif,' 



Field 
of Seed 

Cotton 



Per 

cent of 
Lint 



Total 
Score 



Parental cotton hybrid sheet. Salmon. 9£ x 7 in. (P. B. Form 4.) 



Cotton Hybrid. 
Individual Sheet. 



P. B. Form 5 a. 



Cotton Hybrid No. 



Parentage £> ? x 

Inbred Year Experimenter 



Field Notes {See Notes , page ): 



General Notes : 



Date 
Planted 



First 

Bolls 

Opened 

Earliness 



Height 

Form 

of 
Plant 



Disease 
Resist- 
ance 



Weight 
Ten 

Bolls 
Seed 

Cotton 



Num- 
ber of 
Bolls 



Bolls 



Size 



Opening 



Seed 



Smooth 

or 
Tufted 



Size by 
Weight 



Cover- 
ing 



Lint 



Length 



Color 



Fine- 
ness 



Uni- 
form- 
ity 



Strength 



Dra? 



Yield 
of Seed 
Cotton 



Per 

cent of 

Lint 



Total 
Score 



Progeny Notes {See Notes , page ): 



Locality 
Where 
Grown 



Date 
Planted 



Number 
Plants 
Grown 



Number 
Plants 
Har- 
vested. 



Earli- 
ness 



Height 

Form 

of 
Plant 



Disease 

Resist- 
ance 



Size of 
Bolls 



Open- 
ing of 

Bolls 



Seed 



Size 



Per 

cent 

Smooth 



Per 

cent 
Tufted 



Lint 



Length 



Color 



Fine- 
ness 



Uni- 
form- 
ity 



Strength 



Dra? 



Yield 
of Seed 
Cotton 



Per 

cent oi' 
Lint 



Total 
Score 



Individual cotton hybrid sheet. White. 9} x 7 in. (P. B. Form 5 a.) 



Cotton Selection. 
Introductory Sheet. 



P. B. Form 8. 



Parent Variety 

Notes , page Year Experimenter 



Cotton Series No. 
, U. S.P. B. No. 



Characters of Parent Variety ; 



Object of the Selection : 



Notes on Plants Grown for Selection (See Notes , page .-) : 



Locality 
Where 
Grown 



Date 
Planted 



Number 

Seeds 
Planted 



Number 
Plants 
Grown 



Number 
Plants 
Har- 
vested 



Height 



Disease 

Resist- 
ance 



Opening 
of Bolls 



Seed 



Size 



Per 

cent 

Smooth 



Per 

cent 

Tufted 



Lint 



Length 



Fine- 
ness 



Uni- 
form- 
ity 



Strength 



Drutf 



\ i.l.l Pm 

ni Seed I'l'iit of 

Cotton Lint 



Total 
Boom 



Introductory cotton selection sheet. Blue. 9\ x 7 in. (P. B. Fo 



Cotton Selection. 
Individual Sheet. 



P. B. Form 9 a. 



Parent Variety 
Inbred 



Cotton Selection No. 
, U.S. P. B, No. 



. Year. 



Experimenter 



Field Notes {See Notes , page v 



General Notes 



Date 
Planted 



First 

Bolls 

Opened 

Earliness 



Height 

Form 
of 

Plant 



Disease 
Resist- 
ance 



Weight 
Ten 
Bolls 
Seed 

Cotton 



Num- 
ber of 
Bolls 



Bolls 



Size 



Opening 



Seed 



Smooth 



Tufted 



Size by 
Weight 



Cover- 
ing 



Lint 



Length 



Color 



Fine 
ueu 



i ni 
fortu- 
ity 



Strength 



1 i.-i.i 

Of BMd 

Drug Cotton 



Per 

Cl'lll (>(' 

Lint 



Total 

Si ore 



Progeny Notes {See Notes , page ): 



Locality 
Where 
Grown 



Date 
Planted 



Number 
Plants 
Grown 



Number 
Plants 
Har- 
vested. 



Earli- 
ness 



Height 

Form 

of 
Plant 



Disease 
Resist- 
ance 



Size of 
Bolls 



Open- 
ing of 
Bolls 



Seed 



Size 



Per 

cent 

Smooth 



Per 

cent 

Tufted 



Lint 



Length 



Color 



Fine- 
ness 



Uni- 
form- 
ity 



Strength 



Drag 



Yield 

of Seed 

Cotton 



Per 

(•••nt of 
Lint 



Total 
Score 



Individual cotton selection sheet. White. 94 x 7 in. (P. B. Form 9a.) 



Cotton Score Card. 



P. B. Form 15. 



Cotton Series No. 

Female Parent U. S. P. B. No 

Male Parent U. S. P. B. No.. 



Object of Hybridization or Selection : 



Score on 100 Points 



Earliness 
points, 



Very Early. 

Early 

Medium — 

Late 

Very Late- 



Form of Plant 

points. 



Disease Resist- 
ance 

points, 



Very Resistant 

Resistant 

Medium 

Poor 



Drought Resist- 
ance 

points. 



Very Resistant 

Resistant 

Medium 

Poor 



Opening 1 of 
Bolls 

points. 



Covering of 

Seed 

_ _ points. 



Storm Resist- 
ance 

points. 



Very Resistant 

Resistant 

Medium 

Poor 



Size of Bolls 
points, 



Very Large. 

Large 

Medium 

Small 

Very Small- 



Length of 
Lint 

points 



Very Good 

Good 

Medium __ 
Poor 



Excellent 
Good--- 

Fair 

Poor 



inch . 



1 " -_ 
lx^ inches. 

l 8 

1 3 " 
*!§ 

11 " 
*4 

15 " 

13 " 

1* " ■ 

15 " 
l S 

13 " 
J J 

17 " 

2 " - 

oi " 

2| " - 

2| " - 

91 " 



Color of 
Lint 

points, 



Fineness 
— points, 



Uniformity 
points. 



Strength 
points 



Drag 
_ points. 



Yield 
-points. 



Very Fine 

Fine 

Medium-- 
Coarse 



Excellent - 

Good 

Fair 

Poor 



Very Strong - 

Strong 

Medium 

Weak 



Very Strong - 

Strong 

Medium 

Medium Weak 
Weak 



Excellent 

Good 

Medium 

Light Medium 
Light 



Per cent of 
Lint 



points. 



39 + per cent 
3T-38 per cent 
35-36 per cent 
33-34 per cent 
31-32 per cent 
29-30 per cent 
27-28 per cent 
25-20 per cent 
23-24 per cent 
21-22 per cent 
19-20 per cent 



points, 



points. 



Cotton score card. Yellow. 0J x 7 in. (P. B. Form 15.) 



LECTURE VI. 



POLLINATION; OR HOW TO CROSS PLANTS. 



1. The Structure of the Flower. 

Pollination is the act of conveying pollen from 
the anther to the stigma. It is the manual part 
of the crossing of plants. The word fertilization 
is often used in a like sense, although erroneously ; 
for it is the office of the pollen, not of the opera- 
tor, to fertilize or fecundate that part of the flower 
which is to develop into a seed. 

The chief requirement in pollinating flowers is 
to know the parts of the flower itself. The con- 




Fig. 1. - Bell-flower. 



spicuous or showy part of the flower is the envelope, 
which is endlessly modified in size, form, and color. 

331 



332 



POLLINATION. 



This envelope protects the inner or essential organs, 
and it also attracts insects, which often perform the 
labor of pollination. This floral envelope is usu- 
ally of two series or parts, — an outer and commonly 
green series known as the calyx, and an inner 
and generally more showy series known as the 
corolla. These two se- 
ries are well shown in 
the bell-flower, Fig. 1. 
The calyx, with its re- 
flexed lobes, is at C. 
and the large bell-form 
portion is the corolla. 
When the calyx is com- 
posed of separate parts 
or leaves, each part is 
called a sepal; in like 
manner each separate 
part of the corolla is 
a petal. In the lily, 
Fig. 2, there is no dis- 
tinction between calyx 
and corolla ; or, it may 
be said, the calyx is wanting. These envelopes 
of the flower are often much disguised. This is 
particularly true in the orchids, one of which, a 
lady-slipper, is illustrated in Fig. 3. The sepals 
are seen at DD. They are apparently only two, 
but there is reason to believe that the lower sepal 




Fig. 2. — Flower of white lily. 



THE ESSENTIAL ORGANS. 



333 



is really made up of a union of two. The three 
inner leaves are the petals, the lower one, H, 
being enlarged into the sac or slipper. 

The most important organs of the flower, how- 
ever, to one who wishes to make crosses, are the 
so-called sexual organs, the stamens and pistils. 

They can be readily 
distinguished in the 
lily, Fig. 2. The 
six bodies shown at 
S are the ends of 
the stamens, or so- 
called male organs. 
These stamens gen- 
erally have a stalk 
or stem, known as a 
filament, and the en- 
larged tip as the 
anther. It is in this 
anther that the pol- 
len is borne. The 
pollen is generally 
made up of very mi- 
nute yellow or brown- 
ish grains, although 
it is sometimes in the form of a more or less glu- 
tinous or adhesive mass, as in the milk-weeds and 
orchids. The irritating dust which falls from the 
corn tassels at the later cultivatings is the pollen. 




Fig. 3. — Flower of greenhouse 
cypripediurn. 



334 POLLINATION. 

The pistil, or so-called female organ, is shown at 
OP, Fig. 2. The enlarged portion at O is the 
ovary, which will develop into the seed-pod. The 
stigma, or the enlarged and roughened part which 
receives the pollen, is at P. Between these two 
parts is the slender style, a portion which is absent 
in many flowers. 

The stamens and pistils are known as the essen- 
tial organs of the flower, for, whilst the calyx and 
corolla may be entirely absent, either one or both 
of these organs is present ; and these are the parts 
which are directly concerned in the reproduction 
of the species. Like the floral envelopes, these 
essential organs are often greatly modified, so 
much so that botanists are sometimes perplexed 
to distinguish them from each other or from mod- 
ified forms of the petals or sepals. The particu- 
lar features of these organs which the plant-breeder 
must be able to distinguish are the anther and the 
stigma; for the anther bears the pollen, and the 
stigma must receive it. In Fig. 1, the stamens 
are shown at E. In the flower A, which has just 
expanded, these stamens are rigid and in condition 
to shed the pollen, but in the flower B, they have 
shed the pollen and have collapsed. The stigma 
in this case is divided into three parts, but when 
the flower first opens, these parts are closed to- 
gether, H in flower A, so that it is impossible 
that they receive any pollen from the same flower ; 



THE ESSENTIAL ORGANS. 



335 



when the stamens have withered, however, as in 
B, the stigma, H, spreads open and is ready to 




Fig. 4. — Flower of night-blooming cereus. 

receive any pollen which may be brought to it by 
insects or other agencies. In this case, the ovary 



336 POLLINATION. 

or young seed-pod, which is in the bottom of the 
flower, is not shown in the engraving. 

Some of the particular forms of essential organs 
are well illustrated in the accompanying photo- 
graphs. In the night-blooming cereus, Fig. 4, 
the many-rayed stigma is shown just below the 




Fig. 5. —Flower of the shrubby hibiscus (Hibiscus Syriacus). 

centre of the mouth of the flower, and the nu- 
merous stamens are arranged in a circular manner 
outside of it. The many petals and numerous 
spreading sepals are also well shown. The hibis- 
cus, Fig. 5, has a central column with the anthers 
hanging upon it, and a large stigma raised beyond 



STAMIXATE AND PISTILLATE FLOWERS. 337 




Fig. 6. — Bugbane (Cimicif uga 
racemosa). 



them. The wild bugbane, 
or cimicifuga, is seen in 
Fig. 6, natural size. Here 
is a long spike or cluster 
of flowers. At the top 
are the unopened buds, in 
the centre the expanded 
flowers with the floral 
envelopes fallen away, — 
the fringe-like stamens 
very prominent, — and 
below are seen the pis- 
tils, the stamens having 
fallen. These pistils will 
now ripen into pods, but 
the tip-like stigma may 
still be seen on them. 
The stamens and the long 
protruding style, tipped 
with its stigma, are also 
shown in the fuchsia, 
Fig. 15. The essential 
organs of orchids are cu- 
riously disguised. They 
are combined into a sin- 
gle body. In the lady- 
slipper, Fig. 3, the lip-like 
stigma is shown at P. 
Upon either side, at its 



338 



POLLINATION. 



base, is an anther S. Projecting over the stigma 
is a greenish ladle-like body, T, which is a trans- 
formed and sterile anther. In all lady-slippers, 
these organs are essentially the same as in the 
drawing, although they vary much in size and 
shape ; but in most other orchids, the two side 
anthers, S, are wholly wanting, and the terminal 
organ, T, is a pollen-bearing anther. In numer- 
ous plants, there are many distinct pistils in each 
flower. Such is the case in the strawberry, where 
each little yellow "seed" on the ripened berry 
represents a pistil ; and the blackberry and the 
raspberry, where each little grain or drupelet of 
the fruit stands for the same organ. A flowering 
raspberry is illustrated natural size in Fig. 7, for 
the purpose of showing the ring of many anthers 
near the centre of the flower, inside of which, in 
the very centre, is a little head of pistils. 

It frequently occurs that the stamens and pistils 
are borne in different flowers, rather than together 
in the same flower as they are in the examples 
which we have studied. In these cases the flower 
is said to be staminate, or male or sterile, in one 
case, and pistillate, female or fertile, in the other 
case. If these two kinds of flowers are borne 
together upon the same plant, as in pumpkins, 
melons, cucumbers, chestnuts, oaks, and begonias, 
the plant is said to be monoecious ; but if the stami- 
nate and pistillate flowers are on entirely different 



STAMINATE AND PISTILLATE FLOWERS. 339 

plants,, as in willows and poplars, the plant is dioe- 
cious. The two kinds of squash flowers are 
shown in Fig. 8. The pistillate flower is on 
the left, and it is at once distinguished by the 
ovary or little squash beloAV the colored portion, 




Fig. 7. — Blossom of flowering raspberry (Rubus odoratus). 



or corolla of the flower. The lobed stigma is 
seen in the centre. The st animate flower is on 
the right. It has a longer stem, no ovary, and the 
anthers are united into a conspicuous cone in the 
centre. The flowers expand early in the morning. 
Insects carry pollen to the pistillate flower, which 



340 



POLLINATION. 



then begins to set its fruit, whilst the staminate 
flower dies. The flowers of the common wild 
clematis are shown in Fig. 9. Upon the right 




Fig. 8. — Squash flowers of each sex. 

are the sterile flowers, which are wholly stami- 
nate. On the left, the flowers with larger sepals 
— the petals are absent — have a cone of pistils in 



STAMINATE AND PISTILLATE FLOWERS. 341 

the centre, and a few short and sterile stamens 
spreading from the base of the cone. These dif- 
ferent flowers are borne on different plants in this 
species of clematis, and the plants are therefore 
practically dioecious, because the stamens of the 
pistillate flowers generally bear no pollen. A sim- 
ilar mixed arrangement occurs in some strawber- 




Fig. 9. — Flowers of clematis (Clematis Virginiana). 



ries, except that there are no purely staminate 
flowers. There are purely pistillate varieties, 
others, like the Crescent, with a few nearly or 
quite abortive stamens at the base of the cone of 
pistils, and others in which the flowers are per- 
fect or hermaphrodite, that is, containing the two 
sexes. 



342 POLLINATION. 

The compositous flowers — like the asters, daisies, 
goldenrods, sunflowers, dahlias, zinnias, chrysan- 
themums, and their kin — need to be considered 
in still a different category. In these plants, the 
head, or so-called flower, is an aggregation of sev- 
eral or many small flowers or florets. Each seed 
in a sunflower head, for example, represents a dis- 
tinct flower. Sometimes all of these flowers are 
perfect, — contain the two sexes, — and sometimes 
they are pistillate or staminate in different parts 
of the head ; and in some cases the plants are 
dioecious. In many plants of the composite fam- 
ily, the flowers near the border of the head are 
unlike those of the centre or disc, in having a 
long ray-like corolla ; and these ray-flowers are 
frequently of different form from the others in the 
character of the essential organs. Very frequently 
the ray-flowers are pistillate, whilst the disc-flow- 
ers are generally hermaphrodite. The anthers, in 
these plants, are united in a ring closely about the 
style and below the stigma. 

The ovary, as we have seen, ripens into the 
pod, berry, or other fruit ; but it is not able to 
bear seeds until it is assisted by the pollen. The 
pollen falls upon the roughish or sticky surface 
of the stigma, and there germinates or sends a 
minute tube downwards through the style and 
finally reaches the ovule, which, when fertilized, 
rapidly ripens into the seed. The nature of this 



COMPOSITOUS FLOWERS. 843 

fecundation is not germane to the present subject ; 
but it may be said that only one pollen grain is 
necessary to the fertilization of a single ovule, but 
the addition of a superabundance of pollen greatly 
stimulates the growth of the fleshy or enveloping 
parts of the fruit. It is important that the person 
who desires to cross plants should become familar 
with the stigma when it is "ripe," receptive, or 
ready to receive the pollen. This condition is gen- 
erally indicated by the glutinous or sticky or moist 
condition of the stigma, or in those stigmas which 
are not glutinous it is told by the appearing of a 
distinctly roughened or papillose condition. This 
receptive condition generally occurs about as soon 
as the flower opens. If pollen is withheld, the 
stigma will remain receptive much longer than 
when fertilization has taken place, — in some flow- 
ers for two or three days. 

The pollen is discharged from the anther in 
various ways, but it most commonly escapes 
through a chink or crack in the side of the 
anther. Sometimes it escapes through pores at 
one end of the anther; and in other cases there 
are more elaborate mechanisms to admit of its dis- 
charge. In most plants, the anthers and stigma 
in the same flower mature at different times, so 
that close-fertilization or in-breeding is avoided. 
This is well illustrated in the bell-flower, Fig. 1. 
Here the anthers wither and die before the stig- 



344 POLLINATION. 

matic lobes open. In other cases, the stigma 
matures first, although this is not the usual con- 
dition. 

II. Manipulating the Flowers. 

We are now familiar with the essential principles 
in the pollination of flowers. Before a person pro- 
ceeds to operate upon a flower with which he is 
unfamiliar, he should carefully study its structure, 
so as to be able to locate the different organs, and 
to discover when the pollen and the stigma are 
ready for the work. 

The first and last rule in the pollinating of plants 
is this : Exercise every precaution to prevent any 
other pollination than that ivhich you design to give. 
The anthers, therefore, must be removed from the 
flower before it opens. This removal of the anthers 
is known as emasculation. Just as soon as this 
is done, tie up the flower securely in a bag to 
protect it from foreign pollen which may be 
brought by wind or insects. As soon as the 
stigma is ripe, remove the bag and apply the de- 
sired pollen, placing the bag on the flower again, 
where it must remain until the seeds begin to 
form. The stigma may be receptive the day fol- 
lowing emasculation, or, perhaps, not until a week 
afterwards. Much depends upon the age of the 
bud when emasculation takes place. It is gener- 



EMASCULATING. 



345 



ally best to delay emasculation as long as possible 
and not have the flower open ; but the operator 
must be sure that the anthers do not discharge or 
that insects do not get into the flower before he 
has emasculated it. The bud at B, in Fig. 3, is 




Fig. 10. — Tobacco flowers, showing the parts of the flower, a bud 
ready to be emasculated, and an emasculated subject. 

nearly ready to emasculate. The older buds on 
the top of the spike of bugbane, Fig. 6, are ready 
to operate upon; and so is the bud seen at the 
left in Fig. 7. 

The manner of emasculating the flower varies 



346 POLLINATION. 

with the operator. It is a common practice to 
clip off the anthers with a pair of small scissors, 
or to hook them out with a bent pin or a crochet 
hook. Others use tweezers. For myself, how- 
ever, I do not like any of these methods, because 
the anthers are apt to drop into the bottom of the 
corolla, where it is sometimes difficult to rescue 
them ; and if one uses tweezers, there is always 
danger that the anthers may be crushed and that 
some of the pollen may adhere to the instrument 
and contaminate future crosses. I therefore usu- 
ally cut the corolla completely off just above the 
ovary, with a pair of small, long-handled surgeon's 
scissors (see Fig. 12), removing everything but 
the pistil. The operation is explained in Fig. 10, 
which shows the tobacco flower. The flower at 
the left shows the pin-head stigma in the centre of 
the throat, and the five anthers surrounding it. 
The second flower is spread open for the purpose 
of showing these organs. The third figure is a 
bud in the right condition for operation. The 
right-hand figure shows this bud cut around with 
the points of the scissors, leaving only the pistil. 
The line at W, in Fig. 2, shows where the flower 
of the lily might be cut off. The manner of oper- 
ating upon a compositous flower is shown in the 
picture of the zinnia, Fig. 11. In this plant the 
outer florets of the head are pistillate, whilst those 
of the disc are perfect. It is only necessary, 



EMASCULATING. 



347 



therefore, to remove the central stamen-bearing 
flowers before any of them open, and to cover the 
flower up before any of the pistils near the border 




Fig. 11. — Zinnia flowers ; the upper head ready for emasculation, 
the lower one showing the operation performed. 

have protruded themselves. The upper head in 
Fig. 11 shows the untreated sample, whilst the 
lower one shows the same with the cone of central 



348 POLLINATION. 

flowers pulled out. This treated head should now 
be covered, to await the maturing of the stigmas. 
In many compositous plants, however, the case is 
not so simple as this, because all the flowers are 
perfect. In such cases, nearly all the florets should 
be removed from the head, and a few remaining 
ones emasculated in essentially the same manner 
as described for the tobacco, Fig. 10. Whenever 
flowers are borne in clusters, nearly all of them 
should be removed and the attention confined to 
only two or three of them. One is then more cer- 
tain of getting seeds to set. In some cases, like 
the apple cluster, only one or two flowers of any 
cluster ever set fruit, and the operator should then 
choose the two or three strongest and most prom- 
ising buds, and cut all the. others off. 

Flowers which bear no stamens, as the pistillate 
flowers of squashes, strawberries, and many other 
plants, of course do not require emasculating. 
They should be tied up while in bud, however, to 
prevent the access of any foreign pollen. Indian 
corn is a case in point. The pistillate flowers are 
on the ear, each kernel of corn representing a single 
flower. The silks are the stigmas. If it is desired 
to cross corn, therefore, the ear should be covered 
before any silks are protruded, and the pollen should 
be applied some days later, when the silks are full 
grown. The staminate or male flowers are in the 
tassel. 



APPLYING THE POLLEN. 



349 



The pollen should be derived from a flower 
which has also been protected from wind and in- 




Fig. 12. — Instruments used in pollinating flowers, natural size. 
Pin scalpel, scissors, lens. 



350 POLLINATION. 

sects, because foreign pollen may have been 
dropped upon an anther by an insect visitor and it 
may be unknowingly transferred by the operator. 
The pollen-bearing parent needs no operation, of 
course, but the flower should have been tied up 
in a bag when it was in bud. The pollen is best 
obtained by picking off a ripe anther and crush- 
ing it upon the thumb-nail. Then it is trans- 
ferred to the stigma by a tiny scalpel made by 
hammering out the small end of a pin, as shown, 
full size, at the left in Fig. 12. The stigma 
should be entirely covered with the pollen, if pos- 
sible. It is often advised to use a camel's hair 




Fig. 13. — Ladle for pollinating house tomatoes. 

brush to transfer the pollen, but much of the 
pollen sticks amongst the hairs of the brush and 
is ready to contaminate a future cross ; and where 
the pollen is scarce it cannot be conserved to 
advantage by a brush. In some cases the pollen 
is discharged so freely that the anther may be 
rubbed upon the stigma, or even shaken over it, 
but in most instances it will be necessary to actu- 
ally place the pollen upon the stigma with some 
hard instrument. When pollinating house-grown 
melons and cucumbers, the staminate flower is 
broken off, the corolla stripped back, and the 



KEEPING THE POLLEN. 



351 



anther-cone inserted into the pistillate flower, 
where it is allowed to remain until it dries and 
falls away. In pollinating house tomatoes, an 
implement shown in Fig. 13, one-third size, is 
used. This is simply a watch-glass, T, secured 
to a handle. When the house 
is dry, at midday, the watch- 
glass is held under the flowers, 
which are tapped, and the pol- 
len falls into the glass. The 
glass is then held up under 
another flower until the stigma 
rests in the pollen. It should 
be said, however, that this pol- 
lination of tomatoes is for the 
purpose of making the fruit 
set in the absence of insects, 
j not to effect a cross. If the 
Uf^L^^^JST latter purpose were the object 
sought, the flowers which are 
°li \i !? orcov " to bear the seeds would need 

enng the flowers. 

to be emasculated. 
Sometimes it is impossible to secure the pollen 
at the time the stigma is ready. In some cases 
of this kind, the intended parents can be grown 
under glass so as to bring them into bloom at the 
same time. In other cases, it is necessary to keep 
the pollen for some time. The length of time 
that pollen will keep varies with the species and 




352 



POLLINATION'. 



probably also with the strength and vigor of the 
plant which bears it. As a rule, it will not keep 
more than a week or two, and, in general, it may 







Fig. 15. — Fuchsias, showing the stamens and pistils, and a hud 
ready to he emasculated. 

be said that the^ fresher it is the better it may be 
expected to act. It is best kept in dry and tight 



BAGGING THE FLOWER. 



353 



paper bags, such as are used for covering the 
flowers. 

Something more should be said about the bags 
which are used for covering the flowers. After 
having tried every kind which is recommended, 
I rind grocer's manilla bags much the most satis- 
factory. For most flowers the four-ounce size is 
the handiest. When the bags are still flat, as 




Fig. 10. — Fuchsia flower emasculated. 

they come from the packages, a hole is made 
through the two overlapping folds near the open- 
ing, and a string is passed through it and then 
tied at one of the folds, as shown in Fig. 14. 
The bag is then ready for use. Before it is put 
on the flower, the lower end of it is dipped in 
water to soften it so that it can be puckered 
tightly about the stem and thereby prevent the 



354 



POLLINATION. 



entrance of any in- ' 
sect. A bag is pnt 
upon the seed-bear- 
ing flower when 
emasculation is per- 
formed, and upon 
the intended pol- 
len parent when 
the flower is still 
in bud. The bag 
may be removed 
from the emascu- 
lated flower from 
time to time to ex- 
amine the stigma, 
and again when 
the pollen is ap- 
plied ; but it should 
not be taken off 
permanently until 
the pod or fruit 
begins to grow. 

By way of re- 
capitulation, let us 
consider the cross- 
ing of a fuchsia 
flower. In Fig. 15 
two flowers are shown in full bloom, with the long 
style and the eight shorter stamens. The single 




Fig. 



17. — Fuchsia flower tied up after 
emasculation. 



BAGGING THE FLOWER. 



355 



bud is just the right age to emasculate. We 
therefore cut off the two floivers and emasculate 
the bud, as in Fig. 16. The pollen of another 
flower is applied and the bag is tied on, as seen in 
Fig. 17. The best label is a small merchandise 
tag, and this records the staminate parent and 
the date. 

It will be seen that in the operation of emascu- 
lating the fuchsia flower we cut off the sepals as 




Fig. 18. — Tomato and quince, showing how the sepals were cut off 
in emasculating. 



well as the petals. In some plants the calyx 
adheres to the full-grown fruit, as on the apple, 
pear, cpince, gooseberry, or persists at the base 
of the fruit, as in the tomato, pea, raspberry. In 
these fruits, therefore, the cutting away of the 
calyx leaves an indelible mark which at once dis- 
tinguishes the fruits which have been crossed, 



356 



POLLINATION. 



even if the labels are lost. In Fig. 18 a tomato 
and quince are shown which are thus marked. 

All the foregoing remarks do not apply to the 
crossing of ferns, lycopods, and the like, because 
these plants have no floAvers ; yet cross-fertiliza- 
tion may take place in them. When the spores 




Fig. 19. — Pollinating kit. 

of these flowerless plants are sown, a thin green 
tissue, or prothallus, appears and spreads over the 
ground. In this tissue the separate sex-organs 
appear, and after fecundation takes place, the 
fern, as we commonly understand it, springs forth. 
Thereafter, this fern lives an asexual life and 



IMPLEMENTS USED IN CROSSING. 



357 



produces spores year after year ; but it is only in 
this primitive prothallic stage that fertilization 
takes place, once in the lifetime of the plant. If 
these plants are to be crossed, the only procedure 
open to the gardener is to sow the spores of the 
intended parents together in the hope that a nat 
ural mixing may take place. There are various 
well-authenticated fern hybrids. 

The pollination of flowers is such a simple work 
that few implements are required for its easy 
performance. Great care is more important than 




Fig. 20. — Pollinating kit. 



any number of tools. Every one who expects to 
cross plants should provide himself with the three 
instruments shown in Fig. 12, — a pin scalpel, 
sharp-pointed scissors, and a large hand-lens. If 
one contemplates much experimenting in this 
direction, however, it is economy of time to have 
some sort of a box in which there are compart- 
ments for the various necessities. These various 
compartments suggest at once whatever accesso- 
ries are wanting, and they hold a sufficient supply 



358 



POLLINATION. 



for several hundred operations. There should be 
a compartment for bags, string, lens, scissors, and 
pencils, tags, note-book, and the like. Figs. 19 
and 20 show a convenient case for an experimenter, 
and one which I have used with satisfaction for 
several years. This kit is twelve inches long, 
nine inches wide, and three inches deep. 



* * -K- 



Since the above advice was written, much has 
been said on the subject of methods of pollination. 
Some of the literature is mentioned in the bibli- 
ography at the end of the book. The reader 
should consult Charles P. Hartley, "Injurious 
Effects of Premature Pollination," Bulletin 22, 
Bureau of Plant Industry, United States De- 
partment of Agriculture, 1902, 



GLOSSARY. 

1. The Flower. 

Anther. — That part of the stamen which bears the pol- 
len. It is the uppermost extremity of the stamen. 

Calyx. — The outer series of floral envelopes, usually 
green. The various separate parts of the calyx are 
sepals. 

Corolla. — The inner series of floral envelopes, usually 
colored and forming the showy part of the flower. If 
it is divided into separate parts, these are called petals. 

Essential organs. — The stamens and pistils. 

Female. — Said of flowers which have only pistils or the 
seed-bearing part, or of plants which bear only such 
flowers ; applied also to the pistils in any flower. 

Filament. — The stalk or stem of a stamen, bearing the 
anther. 

Floral envelopes. — The calyx and corolla. 

Male. — Said of flowers which bear only stamens, or of 
plants which have only staminate flowers ; also applied 
to the stamens or pollen-bearing organs of flowers. 

Ovary. — The lowest part of the pistil, containing the 
ovules. It is the most thickened portion of the pistil, 
and it may stand either below or above the petals. 
The ovary ripens into the fruit. 

Ovule. — A body in the ovary which ripens into a seed. 

Pet'-al. — The separate parts or leaves of the corolla. 

Pistil. — The seed-bearing organ of the flower. It always 
comprises two parts, the ovary — which becomes the 
pod or fruit — and the stigma. Usually there is a 

359 



360 GLOSSARY. 

style connecting the two. Often called the fertile or 
female organ. 

Pistillate. — Said of a plant or flower that has only pistils 
or seed-bearing organs. 

Pollen. — The contents of the anther, capable of fertil- 
izing the forming ovules. It is usually composed of 
minute yellow or brown grains or spores. 

Se'-pal. — The separate portions or leaves of the calyx. 

Spore. — A reproductive body, sometimes asexual, by 
means of which "flowerless plants" propagate; also 
pollen-grains and embryo-sacs. 

Stamen. — The pollen-bearing organ of the flower. Often 
called the male or sterile organ. Its essential part is 
the anther. The stalk, when present, is called the 
filament. 

Staminate. — Said of a plant or flower that bears only 
stamens or pollen-bearing organs. 

Stigma. — The top end of the pistil, where the pollen 
lodges and germinates. It is usually a somewhat ex- 
panded surface, and is roughened, or sticky, or moist 
when ready to receive the pollen. 

Style. — The more or less slender portion of the pistil 
which lies between the stigma and ovary. The pol- 
len-tubes pass through it in reaching the ovary. 
2. Crossing. 

Bigener; bigeneric-hybrid. — A hybrid between species of 
different genera. 

Bigeneric half-breed. — The product of a cross betweeu 
varieties of species of different genera. 

Close-fertilization ; self-fertilization. — The action of pollen 
upon the pistil of the same flower. 

Close-pollination ; self-pollination. — The transfer of pollen 
to a pistil of the same flower. 

Cross. — The offspring of any two flowers which have 
been cross-fertilized. 



GLOSSARY. 361 

Cross-breed : half-breed ; mongrel. — A cross between varie- 
ties of the same species. 

Cross-fertilization. — The action of pollen npon the pistil 
of another flower of the same species. 

Crossing. — The operation or practice of cross-pollinating. 

Cross-pollination. — The conveyance of pollen to the 
stigma of another flower. 

Derivative- or derivation-hybrid ; secondary-hybrid. — A hy- 
brid between hybrids, or between a hybrid and one of 
its parents. 

Fertilization ; fecundation ; impregnation. — The action of 
the pollen upon the forming ovules. 

Half-hybrid. — The product of a cross between a species 
and a variety of another species. 

Hybrid. — The offspring of crossed plants of different 
species. (See page 284.) 

Hybridism ; hybridity. — The state, quality, or condition 
of being a hybrid. 

Hybridization. — The state or condition of being hybrid- 
ized, or the process or act of hybridizing. 

Hybridizing. — The operation or practice of crossing be- 
tween species. 

Individual cross. — The offspring of two crossed flowers 
on the same plant. 

Individual fertilization. — Fertilization between flowers 
upon the same plant. 

Mongrel. — A cross. 

Mule. — A sterile (seedless) hybrid. 

Pollination. — The conveyance of pollen from the anther 
to the stigma (page 252). 

The term cross is used to denote the offspring of any 
sexual union between plants, whether of different 
species or varieties, or even different flowers upon the 
same plant. It is a general term. And the word is 



362 GLOSSARY. 

also sometimes used to denote the operation of pei« 
forming or bringing about the sexual union. There 
are different kinds of crosses. One of these is the 
hybrid. A hybrid is a cross between two species, as a 
plum and a peach, or a raspberry and a blackberry. 
There has lately been some objection urged against 
this term, because it is often impossible to define the 
limitations of species, — to tell where one species ends 
and another begins. And it is a fact that this diffi- 
culty exists, for plants which some botanists regard as 
mere varieties others regard as distinct species. But 
the term hybrid is no more inaccurate than the term 
species, upon which it rests ; and, so long as men talk 
about species, so long have we an equal right to talk 
about hybrids. Here, as everywhere, terms are mere 
conveniences, and they seldom express the whole truth. 
The word hybrid is used in the above sense in this 
book, with the exception of the new matter now 
contained in Lecture IV., in which the newer concep- 
tion is explained. For an explanation of this change 
in definition, see pages 153, 154. 
3. Classification. 

Break. — A radical departure from the type. Ordinarily 
used in the sense of sport, but in its larger meaning it 
refers to the permanent appearance of apparently new 
or very pronounced characters in a species. 

Bud-variation. — Variation or departure from a type 
through the agency of buds (pages 28, 191). 

Bud-variety. — A variety resulting from bud-variation. 
Bud-sport. 

Family (Order in botany.) — A group of genera and 
species; as Cupuliferoz, the Oak Family, Rosacea, the 
Rose Family. 

Form. — A minor variety, usually transient, produced by 
some local environment. 



GLOSSARY. 363 

Genus (plural, genera). — A group or kind comprising a 
greater or less number of closely related species; as 
Acer, the maples, Fragaria, the strawberries. 

Mutation. — A term proposed by De Vries to desig- 
nate the "leaps" or "jumps" whereby species are 
thought to originate. More definite and specific than 
" sport." (See Lecture IV.) 

Race. — A fixed cultural variety ; that is, a cultural va- 
riety which reproduces itself more or less uniformly 
from seeds. 

Seedling. — A plant growing directly from seed, without 
the intervention of grafts, layers, or cuttings. 

Seed-variation. — Variation or departure from a type 
through the agency of seeds. 

Seed-variety. — A variety resulting from seed-variation. 

Species (plural also species). — A term used to designate 
a group of individuals of sufficient distinctness and 
definiteness to be used as a unit in classification. It 
is an indefinite term, differently used by different 
authors. The species-group does not necessarily rep- 
resent an entity in nature. 

Sport. — A variety or variation which appears suddenly 
and unaccountably, either from seeds or buds; some- 
times, but unnecessarily, restricted to varieties origi- 
nating from buds, as in this book. 

Stock. — The parentage of a particular strain or variety. 

Strain. — A sub-variety, or individuals of a variety, which 
has been improved and bred under known conditions. 

Variation. — 1. The act or condition of varying or be- 
coming modified. 2. A transient variety, more or less 
incapable of being fixed or rendered permanent. 

Variety. — A form or series of forms of a species marked 
by characters of less permanence or less importance 
than are the species themselves. 

Wilding. — A wild individual from a cultivated species. 



BIBLIOGRAPHY. 

Following is a list of miscellaneous references to writ- 
ings on subjects related to plant-breeding. It is not intended 
to be either complete or comprehensive ; but it is sufficient 
to give the beginning student a fair conception of the range 
and extent of the literature, and it will enable him to select 
writings on specific questions that he may be studying. It 
has purposely been confined largely to horticultural writings. 

The literature of cross-fertilization (or cross-pollination) 
itself — the means by which flowers are pollinated — has 
been omitted. Those who desire a bibliography of this 
subject should consult d'Arcy Thompson's list in Mueller's 
" Fertilization of Flowers." 

In the present list I have included many references to the 
subject of the immediate influence of pollen, although mak- 
ing no special effort to collect such entries. 

The proofs have been examined by G. Harold Powell and 
H. J. Webber of the United States Department of Agriculture, 
and by W. M. Hays of the University of Minnesota, and 
others, who have added references. It has not been possible 
to verify all the added titles. 

1724. Dudley, P. An Observation on Indian Corn. Trans. 
Roy. Phil. Soc. vi. (2), 204-205. 

1745. Cooke, Benj. Concerning the Effect which the Farina 
of the Blossoms of different sorts of Apple trees had on the 
fruit of a neighboring Tree. Trans. Roy. Phil. Soc. ix. 169. 

365 



366 BIBLIOGRAPHY. 

1748. Cooke, Benj. On a mixed Breed of Apples, from the 
Mixture of the Farina. Trans. Royal Phil. Soc. ix. 599. 

1749. Cooke, Benj. On the Effects of the Mixture of the 
Farina of Apple trees ; and of the Mayze or Indian Corn, 
etc. Trans. Royal Phil. Soc. ix. 685. 

1761. Koelreuter, Joseph Gottlieb. Vorlaufige Nachricht 
von einigen das Geschlecht der Pflanzen betreffenden 
Versuchen und Beobachtungen. 50 pp. Leipzig. Con- 
tinued in 1763, 1764, and 1766. [Republished in 1893 as 
No. 41 in Ostwald's " Klassiker der Exakten Wissen- 
schaften." Berlin.] 

1793. Sprengel, Christian Konrad. Das entdeckte Geheim- 
niss der Natur im Bau und in der Befruchtung der 
Blumen. 444 pp. 25 tab. Berlin. 

1806. Knight, Thomas Andrew. Observations on the 
Means of Producing New and Early Fruits. Trans. 
Royal Hort. Soc. i. 30. Reprinted in Physiological 
and Horticultural Papers of Thomas Andrew Knight, 
172. 

1809. Knight, Thomas Andrew. On the Comparative In- 
fluence of Male and Female Parents on their Offspring. 
Trans. Royal Phil. Soc. 1809, pt. i. 392 ; Phys. and Hort. 
Papers, 343. 

1814. Knight, Thomas Andrew. An Account of two New 
Varieties of Cherry. Trans. Royal Hort. Soc. ii. 137. 

1816. Knight, Thomas Andrew. An Account of three New 
Peaches. Trans. Royal Hort. Soc. ii. 214. 

1817. Knight, Thomas Andrew. An Account of a Peach 
tree produced from the Seed of the Almond tree, with 
some Observations on the Origin of the Peach tree. 
Trans. Royal Hort. Soc. iii. 1. 

1818. Herbert, W. Instructions for the Treatment of the 
Amaryllis longiflora, as a hardy Aquatic, with some 
Observations on the Production of Hybrid Plants, and 



BIBLIOGRAPHY. 3G7 

the Treatment of the Bulbs of the Genera Crinum and 
Amaryllis. Trans. Royal Hort. Soc. iii. 187. 

1818. Knight, Thomas Andrew. Upon the Variations of 
the Red Currant when propagated by Seed [Crosses of 
white and red currants]. Trans. Royal Hort. Soc. iii. 86. 

1818. Knight, Thomas Andrew. Upon the Variations of 
the Scarlet Strawberry (Frugaria Virginiana) when propa- 
gated by Seeds. Trans. Royal Hort. Soc. iii. 207. 

1818. Knight, Thomas Andrew. Description of a New 
Seedling Plum. Trans. Royal Hort. Soc. iii. 214. 

1818. Sabine, Joseph. Observations on, and Account of, 
the Species and Varieties of the Genus Dahlia; with In- 
structions for their Cultivation and Treatment [Refers 
to Experiments in Crossing]. Trans. Royal Hort. Soc 
iii. 217. 

1818. Van Mons, Jean Baptiste. Substance of a Memoir 
on the Cultivation and Variation of Brussels Sprouts. 
Trans. Royal Hort. Soc. iii. 197. 

1819. Anderson, David. Account of a New Melon, with a 
Description of the Method by which it was obtained. 
Trans. Royal Hort. Soc. iv. 318. 

1819. Herbert, W. On the Production of Hybrid Vege- 
tables; with the Result of many Experiments made in 
the Investigation of the Subject. Trans. Royal Hort. 
Soc. iv. 15. 

1820. Sabine, Joseph. Account of a Newly Produced Hy- 
brid Passiflora. Trans. Royal Hort. Soc. iv. 258; also 
v. 70 (1822). 

1820. Turner, John. Observations on the Accidental Inter- 
mixture of Character of Certain Fruits. Trans. Royal 
Hort. Soc. v. 63. 

1821. Gowen, Robt. On the Production of a Hybrid Ama- 
ryllis. Trans. Royal Hort. Soc. iv. 498. 

1821. Guillemin et Dumas. Observations sur l'hybridite 



368 BIBLIOGRAPHY. 

des Plantes en General et particulierement sur celle de 
quelques Gentianes alpines. Mem. Soc. Nat. Hist. Paris, 
i. 79-92. 

1821. Knight, Thomas Andrew. Observations on Hybrids. 
Trans. Royal Hort. Soc. iv. 367 ; Phys. and Hort. Papers, 
251. 

1822. Goss, John. On the Variation in the Color of Peas, 
occasioned by Cross Impregnation. Trans. Royal Hort. 
Soc. v. 234. 

1823. Gowen, Robt. Description of Amaryllis psittacina- 
Johnsotii, a New Hybrid Variety raised by William 
Griffin, Esq., and recently flowered in the Collection at 
Highclere. Trans. Royal Hort. Soc. v. 361. 

1823. Gowen, Robt. On a Hybrid Amaryllis produced be- 
tween Amaryllis vittata and Amaryllis regina-vittata. 
Trans. Royal Hort. Soc. v. 390. 

1823. Knight, Thomas Andrew. An Account of some 
Mule Plants. Trans. Royal Hort. Soc. v. 292 ; Phys. and 
Hort. Papers, 275. 

1823. Knight, Thomas Andrew. Some Remarks on the 
Supposed Influence of the Pollen, in Cross-Breeding, upon 
the Color of the Seed-Coats of Plants, and the Qualities 
of their Fruits. Trans. Royal Hort. Soc. v. 377 ; Phys. 
and Hort. Papers, 278. 

1823. Knight, Thomas Andrew. An Account of a New 
Variety of Plum, Called the Downton Imperatrice. 
Trans. Royal Hort. Soc. v. 381. 

1823. Lindley, John. A Notice of Certain Seedling Varie- 
ties of Amaryllis, presented to the Society by the Hon. 
and Rev. William Herbert, in 1820, which flowered in 
the Society's Garden in February, 1823. Trans. Royal 
Hort. Soc. v. 337. 

1824. Knight, Thomas Andrew. Observations upon the 
Effects of Age upon Fruit Trees of Different Kinds; with 



BIBLIOGRAPHY. 369 

an Account of some New Varieties of Nectarines. Trans. 

Royal Hort. Soc. v. 384. 
1826. Sageret, Augustin. Considerations sur la production 
des hybrides, des variantes et des varietes en general, et 
sur celle de la famille des Cucurbitacees en particular. 
Ann. Sci. des Nat. Bot. viii. 294-314. 

1826. Wiegmann, A. F. Ueber Bastarderzeugung im Pflan- 
zenreiche. 

1827. Hamelin, Baron. On the Hybrids Obtained by 
Baron Melazzo and others. Annales de la Soc. d'Hort. 
de Paris, i. No. 2, Oct. Abstr. in Gar. Mag. iii. 443. 

1828. Sweet, R. The Permanency of Hybrids. Gar. Mag. 
iv. 182. 

1830. Gowen. Hybrid Azaleas. Edward's Bot. Reg. 1830, 
No. viii. 1365, Vol. iv. 1407. Abstr. in Gar. Mag. vii. 62, 
471. 

1830. Newman, Jno. The Influence of Parent on Off- 
spring. Gar. Mag. vi. 499. 

1831. Hybrid Rhododendron. Brit. Flower Garden, No. 
xxiii. n. s. 91. Abstr. in Gar. Mag. vii. 341. 

1831. Hybrid Rhododendrons. Edward's Bot. Reg. iv. 

1413. Abstr. in Gar. Mag. vii. 205. 
1831. Lindley, John. Various Notes on Hybridization, in 

"A Guide to the Orchard and Kitchen-Garden. London, 

1831." Abstr. in Gar. Mag. vii. 579. 
1831. Potentilla Russelliana. Bot. Garden, No. lxxvi. 304. 

Abstr. in Gar. Mag. vii. 343. 
1831. Remarks on Hybrids. Florists' Guide, No. xliv. 174. 

Abstr. in Gar. Mag. vii. 205. 

1831. Saunders, Wm. Hybrid Rhododendron. Gar. Mag. 
vii. 135. 

1832. Dutrochet. The Sterility of Hybrid Plants. Gar. 
Mag. viii. 500. 

1832. Graham, Dr. Hybrid Poppies. Gar. Mag. viii. 355. 



370 BIBLIOGRAPHY. 

1832. Henslow, J. S. On the Examination of a Hybrid 
Digitalis. Gar. Mag. viii. 208. Extract from pamphlet. 

1832. J. C. K. Hardihood of Hybrid Melons. Gar. Mag. 
viii. 52. 

1832. Mallet, Robert. Hybrid Melons. Gar. Mag. vii. 87. 

1832. Oliver, J. A Hybrid of the Cucumber with the 
Maltese Melon. Gar. Mag. viii. 611. 

1832. Wimmer, C. F. H. Ueber einen Bastard aus der 
Gattung Digitalis. Breslau Schles. Gesell. Uebersicht, 
61-62 ; also 1835, 85. 

1835-6. Van Mons, Jean Baptiste. Arbres Fruitiers ou 
Pomologie Beige Experimental et Raisonnee. 2 vols. 12°. 
Louvain. 

1837. (Editorial.) Cabbage and Horse-Radish . Hovey's 
Mag. Hort. iii. 351. 

1837. Herbert, W. Amaryllidacese, with a Treatise upon 
Cross-bred Vegetables. London. 

1841. Knight, Thomas Andrew. A Selection from the 
Physiological and Horticultural Papers published in the 
Transactions of the Royal and Horticultural Societies, 
by the late Thomas Andrew Knight. To which is added 
a sketch of his life. 379 pp. London. 

1841. Wimmer, C. F. H. Ueber 6 Weidenbastarde. Bres- 
lau Schles. Gesell. Uebersicht, 93-94. 

1843. Wimmer, C. F. H. Ueber die Hybriditat im Pflan- 
zenreiche. Breslau Schles. Gesell. Uebersicht, 208-209. 

1844. (Editorial.) Hybridizing. Gar. Chron. 1844, 459. 
1844. Gaertner, Karl Friedrich. Beitrage zur Kenntniss 

der Befruchtung. 644 pp. Stuttgart. 

1844. Godron, D. A. En l'hybridite dans les vegetaux. 22 
pp. Xancy. 

1845. L. Hybrids in Turnips. Gar. Chron. 1845, 173. 
1845. Lecoq, H. Fecondation naturelle et artificiel du 

vegetaux. Paris. Second edition, 1862. 






BIBLIOGRAPHY. 371 

1845. O. Hybrid between a Yellow Picotee and a Red 

Picotee. Gar. Chron. 1845, 363. 
1847. Herbert, W. On Hybridization amongst Vegetables. 

Journ. London Hort. Soc. ii. 1, 81. 
1847. Morton, S. G. Hybrid Plants. Am. Journ. Sci. and 

Arts, 2 ser. iii. 209. 

1847. Wimmer, C. F. H. Ueber die Hybriditat der Weiden. 
Breslau Schles. Gesell. Uebersicht, 124-131. 

1847-8. Regel, E. Ueber Varietaten und Bastarde im 
Pflanzenreiche. Mittheil. Zurich, i. Heft 2, 69-71. 

1848. Loiseleur-Deslongchamp. Observations sur les plantes 
dont les fleurs paraissent de refuser a l'Hybridation. Rev. 
Hort. 3 ser. ii. 149. 

1848. Mackenzie, G. S. An Account of Some Hybrid 
Melons. Journ. London Hort. Soc. iii. 299. 

1849. Gaertner, Karl Friedrich. Versuche und Beobach- 
tungen liber die Bastarderzeugung in Pflanzenreich. 
791 pp. Stuttgart. 

1849. Laherard, Jerome. Raisin precoce Malingre. Rev. 

Hort. 3 ser. iii. 444. 
1849. Pepin. Hybrides des Abutilon striatum et venosum. 

Rev. Hort. 3 ser. iii. 46. 

1849. Wimmer, C. F. H. Uebersicht der bisher bekannt 
gewordenen Bastarde von Salix. Breslau Schles. Gesell. 
Uebersicht, 87-93. 

1850. Berkeley, M. J. Gaertner's Observations upon Muling 
among Plants. Journ. Hort. Soc. v. 156; vi. 1 (1851). 

1850. Naudin, C. Hybridation des Orchidees. Rev. Hort. 
3 ser. iv. 9. 

1850. Stan dish and Noble. A Chapter in History of Hy- 
brid Rhododendrons. Journ. London Hort. Soc. v. 271. 

1851. Decaisne, J. Hybridation. Rev. Hort. 3 ser. v. 62. 

1852. Rousselon and others. Sur l'Hybridation. Ann. 
d'Hort. de Paris, xliii. 35. 



372 BIBLIOGRAPHY. 

1852. Weddell, H. A. Description d'un cas remarqueble 
d'hybridite, entre des Orchide'es de genres differents. 
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402 



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INDEX. 



Acclimatization, 24, 26. 

Acquired characters, 14. 

Altitude and plants, 25. 

Ainarantus retroflexus, 238. 

Amelioration, gradual, 50. 

American Breeders' Association, 230. 

Animal and plant contrasted, 5, 91. 

Annee, 141. 

Antagonistic features, 95. 

Anther, 335, 361. 

Apple, Wealthy, 108. 

Apples, bud-variation in, 118. 

Apples, hybrid, 66, 79, 111. 

Apples, races of, 90. 

Apples, variations in, 3, 27, 37, 99, 131. 

Arthur, 103, 116. 

Asexual propagation, 7. 

Atavism, 106, 151. 

Bag for covering flowers, 353, 355. 

Bartel, T. C, 130. 

Barteldes, 140. 

Bateson, 156. 

Bean-breeding, 247. 

Beans, types of, 135. 

Beet, crosses, 56. 

Begonia pollinations, 86. 

Bell-flower, 333. 

Bennett, A. W., 276. 

Bibliography, 3G7. 

Bigener, 362. 

Bigness, variation in, 18. 

Blackberry, crosses, 79, 111. 

Blackberry, introduction of, 129. 

Bohnhof, 80. 

Braun, Alexander, 17. 

Break, 364. 

Breaking the type, 19, 23, 93. 



Bruant, 113. 

Buckwheat, crosses, 56. 

Budd, Professor, 133. 

Bud-variation, 6,21, 28,37, 101, 118, 126. 

Bud- variation, definition of, 364. 

Bugbane, 339. 

Burbank, Luther, 238. 

Burpee, 139. 

Cabbage, crosses, 56. 
Cactus, spineless, 243. 
Calyx, 334, 361. 
Canary-grass, crosses, 57. 
Cannas, 140. 

Carleton.M. A., 230, 276. 
Carleton, M. A., article by, 291. 
Carman, 79. 
Carnation, 115. 
Carriere, 96, 116, 143. 
Cereus, night-blooming, 337. 
Change of seed, 28, 59, 116. 
Checking growth, 116. 
Cherry, hybrid, 112. 
Choice of variations, 31. 
Chrysanthemum carinatum, 100. 
Cimicifuga racemosa, 339. 
Citrange, 277, 279. 
Citrus-breeding, 27S. 
Clematis, flowers, 343. 
Climate and variation, 24, 114. 
Close-fertilization, 362. 
Close-pollination, 362. 
Cobey, W. W., 276. 
Coleus, sports in, 120. 
Colors, modified by climate, 25. 
Contradictory attributes, 98. 
Convolvulus pollinations, 85. 
Corn-breeding, 209. 



479 



480 



INDEX. 



Corolla, 334, 361. 
Correns, 156, 197, 
Cotton-breeding, 284. 
Crabs, hybrid, 66, 111. 
Cross, definition of, 362. 
Cross, function of, 50. 
Crosses, characteristics of, 68. 
Crossing a means, 107. 
Crossing and change of seed, 59. 
Crossing, limits of, 44. 
Crossing, philosophy of, 39. 
Crossing, rule for, 109. 
Crozy, 113, 140. 
Cucumber pollinations, 85. 
Cucurbits Pepo, 75, 84. 
Cucurbitacea?, crosses, 46, 5S, 74, 82. 
Cultivation, philosophy of, 22. 
Cypripedium, 335. 

Darwin, 17, 23, 32, 42, 47, 51, 54, 56, 
60, 63, 69, 72, 84, 87, 117, 119, 121, 
145, 233. 

Darwinism, principle of, 145. 

Dating back, 106. 

De Candolles' law, 261. 

Derivative-hybrid. 363. 

De Tries. 145. 147, 148, 149, 150, 155, 
176, 233. 

Dewberry, crosses, 79, 111. 

Dewberry, introduction of, 129. 

Dkecious plants, 341. 

Divergence of character, 23. 

Division of labor, 42. 

Dwarfing, 25, 114. 

Eckford, 113. 

Egg-plant, crosses, 57, 74. 
Egg-plant pollinations, 85. 
Egg-plants, variation in, 95. 
Egypt, plagues of, 40. 
Emasculation. 346. 
Envelopes, floral, 333. 
Environment and variation, 12. 
Equilibrium of organisms, 20, 61. 
Essential organs, 336, 361. 
Experiment Station work, 255. 

Eairchild, David, 238. 
Fall sowing, 115. 



Family, 364. 
Female, 361. 
Ferns, crossing, 358. 
Fertility of soil, 18, 22. 
Fertilization, 362, 363. 
Filament, 335, 361. 
Fittest, survival of, 32, 39. 
Fixation of plants, 31. 
Flavor, modified by climate, 25. 
Floral envelopes, 361. 
Flowerless plants, crossing, 358. 
Focke, 68, 81, 108, 143, 156. 
Food supply, 16, 116. 
Form, definition, 364. 
Fortuitous variation, 9. 
Fraser, Samuel, 266. 
Fruits, for Northwest, 260. 
Fuchsia flowers, 354, 355, 356. 
Function of the cross, 50. 
Funk, J. Dwight, 230. 

Gauss, E., 230. 

Genera, monotypic, 97. 

Genus, 365. 

Gibb, Charles, 133. 

Gideon, Peter M., 108. 

Glossary, 361. 

Goff, 103. 

Gossypium, 285. 

Gourd, crosses, 58, 74, 82. 

Grapes, hybrid, 66, 78, 110, 111. 

Gray, Asa, 33. 

Greenhouses, produce variation, 115. 

Hallock, V. H., & Son, 124. 
Hansen, N. E., article by, 260. 
Hartley, C. P., 230, 276, 360. 
Hays, 216, 218. 
Henderson, 138. 
Heredity, 149, 155. 
Hibiscus S} r riacus, 338. 
Hieracium, 162. 
Hopkins, 207, 209. 
Hopkins, A. D., 230. 
Husk-tomato, 60, 85. 
Hybrid, definition of, 153, 154, 363, 364. 
Hybridization, 189. 

Hybridization, Mendel's experiments 
in, 157, 158, 159. 



INDEX. 



481 



Hybrids, characters of, 68, 178, 179. 
Hybrids, formula for, 161. 
Hybrids, rarity of, 53. 

Ignotum tomato, 123. 
In-breeding, 72. 
Indeterminate varieties, 87. 
Individual cross, 363. 
Individuality, causes of, 8. 
Individuality, fact of, 2. 
Instruments for pollination, 351. 
Ipomoeas, colors of seeds, 104. 
Isolation of the plant, 22. 

Keeney, Mr., 247. 

Keyser, Alvin, 230. 

Knight, Thomas Andrew, 17, 54. 

Kohl-rabi, 80. 

Kolreuter, 54, 73. 

Korschinsky, 150. 

Kumerle, W. J., 140. 

Labor, division of, 42, 48. 
Ladle for pollinating, 352. 
Latitude and plants, 25. 
Leafiness, 25. 
Lemoine, 113. 
Lens for pollinating, 351. 
Lettuce, crosses, 56. 
Lightning-rod boom, 229. 
Lily, white, 334. 
Lima beans, 138. 
Limits of crossing, 44. 
Lindley, 68. 
Links, missing, 41, 48. 
Linnaeus, 81. 

Lupines, heredity in, 106. 
Lycopods, crossing, 358. 

Macfarlane, 195, 196. 

Maize, crosses, 56. 

Male, 361. 

Maple, "VVier's, 109. 

Meadow, plants in, 23. 

Mendel, 156, 157. 158, 174, 176, 197. 

Mendel's law, 161, 166, 172. 

Mersereau, 131. 

Mirabilis pollinations, 85, 

Missing links, 41. 



Mixing in the hill, 118. 

Mongrel, 363. 

Monoecious plants, 340. 

Monotypic genera, 97. 

Montgomery, E. G., 230. 

Moore, Jacob, 110. 

Morning-glory, 54. 

Morong, Dr. Thomas, 60. 

Morus multicaulis craze, 229. 

Mulberry, Teas', 109. 

Mule, 363. 

Munson, Professor, 58. 

MunsoB, T. V., 79, 111. 

Muskmelon pollination, 85. 

Mutation-periods, 149. 

Mutation theory, points of, 152, 191. 

Mutations, 146, 147, 148, 192, 365. 

Natal variations, 15. 
Natural selection, 32, 51. 
Nebraska Corn Society, 230. 
Nectarine, origin of, 118. 
Nicotiana, crosses, 73. 
Nicotiana pollinations, 85, 86. 
Northwest, fruits for, 260. 

Ontario plant-breeding, 255. 
Opuntia, spineless, 243. 
Orchids, hybrids, 79. 
Orton, W. A., 276. 
Ovary, 336, 344, 361. 

Palmer, Asa, 139. 
Pangenes, 125. 
Panmixia, 147. 
Parents, influence of, SI. 
Pea-breeding, 247. 
Peach, bud-variation in, 118. 
Peach, hybrids, 47. 
Peaches, races of, 91. 
Pears, hybrid, 66, 79, 111. 
Pears, variation in, 99. 
Peas, viney, 16. 
Pedigree records, 308. 
Pepino pollinations, 86. 
Pepino, variation in, 95. 
Pepper, red, pollination, 85. 
Peppers, variation in, 96. 
Petal, 334, 361. 



482 



INDEX. 



Petunia pollinations, S5, 86. 

Physalis, 60. 

Physalis, variation in, 96. 

Pigweed, 235. 

Pineapple-breeding, 283. 

Pistil, 336, 361. 

Pistillate, 362. 

Pliny, 131. 

Plum, hybrids, 47, 112. 

Plumcot, 243. 

Plums. Japanese, 27. 

Pollen^ 335, 345, 362. 

Pollinating kit, 358. 

Pollination, 333, 362, 363. 

Pollination, uncertainties of, 83. 

Polytypic genera, 97. 

Position, advantage of, 22. 

Post-natal variations, 15. 

Potato, 37, US. 

Potato and tomato, 95. 

Potato, seedlessness, 99. 

Propagation, asexual, 7. 

Protein in corn, 211. 

Pruning, 23. 

Pumpkin, crossing, 46, 58, 74, 82. 

Quince, pollinated, 357. 

Pace, definition, 365. 

Paces in fruits, 90. 

Radish pollinations, 85. 

Paphanus Paphanistrum, 116. 

Raspberry, flowering, 341. 

Raspberry, hybrids, 79, 111. 

Records, 308. 

Red-root, 235. 

Representative species, 66. 

Rogue, 89, 127. 

Rose, bud-varieties in, 118. 

Rubus odoratus, 341. 

Running out of varieties, 36, 125. 

Russia, fruits from, 27, 90, 133. 

Rye, hybrids, 79. 

Salter, 119. 
Saunders, D. A.. 276. 
Scalpel for pollinating, 351. 
Scissors for pollinating, 351. 
Seed, change of, 28, 59. 



Seedling, 365. 

Seeds, colors of, 104. 

Seeds, immature, 103. 

Seeds, large and small, 101. 

Seed- variation, 365. 

Selection and progress, 120, 122, 127. 

Selection, natural, 32, 51, 146. 

Selection, natural, of two categories, 

148. 
Self-fertilization, effects of, 54. 
Sepal, 334, 362. 
Sex and variation, 11, 43. 
Shamel, A. D., 276. 
Shoemaker, D. N., 276. 
Societies of breeders, 230. 
Solanum, variations in, 95. 
South Dakota, breeding in, 262. 
Species, 195. 

Species, catogories of, 151. 
Species, conceptions of, 153. 
Species, definition, 365. 
Spencer, 61. 
Spillman, 17S, 181. 
Spore, definition, 362. 
Sports, 2-2. 28, 37, 191, 365. 
Sprengel, 54. 

Squash, crosses, 58, 74, 82. 
Squash flowers, 342. 
Squash, Hubbard, 46. 
Stamens. $$b, 362. 
Staminate, 362. 
Stigma, 336, 362. 
Stock, definition, 365. 
Strain, definition, 365. 
Strawberry, Wilson, 125. 
Struggle for life, 20, 29, 39. 
Sturtevant, 103. 
Style, 336, 362. 
Survival of the fittest, 32, 39. 
Swamping effects of inter-crossing, 46. 
Swingle, W. T., 283. 
Synchronistic variations, 117. 

Tangelo. 2S1. 

Teas, Mr., 109. 

Thinning, 23. 

Tillage and food supply, 17, 22. 

Timothy -breeding, 266. 

Tobacco flowers, 347. 



INDEX. 



483 



Tobacco pollinations, 86. 
Tomato and potato, 95. 
Tomato, crosses, 5S. 
Tomato, Ignotum, 123. 
Tomato, pollinated, 357. 
Tomato pollinations, 85. 
Tomato, Trophy, 37. 
Tomato, variation in, 98. 
Tomatoes, breeding, 103. 
Townsend, C. 0., 276. 
Triticum monococcuin, 307. 
Tschermak, 150, 197. 

United States Department of Agricul- 
ture, 276. 

Variability, variation in, 25. 
Variation and environment, 12. 
Variation caused by sex, 11, 43. 
Variation, definition, 365. 
Variation, fortuitous, 9. 
Variation, philosophy of, 1. 
Variation, proper, 145, 146. 
Variations, choice of, 31. 
Variations, fixation of, 31. 
Variations, natal and post-natal, 15. 



Variations, origin of, 8, 41. 

Variations, two kinds, 145. 

Variegation, perpetuating, 120. 

Varieties, running out, 36, 125. 

Variety, 195. 

Variety, definition, 365. 

Variety, what is a, 35, 205. 

Verlot, 121, 143. 

Vilmorin, Henri L. de, 100, 105, 142. 

Yilmorin, Louis Leveque de, 106. 

Walker, Ernest, 120. 

Wallace, 47, 60, 67. 

Watermelon pollination, 85. 

Webber, 197. 

Webber, articles by, 278, 283, 284, 308. 

Weismann, 13, 14, 147. 

Wheat-breeding, 216, 291. 

Wheat, hybrids, 79, 180, 183. 

Wier, D. B., 109. 

Wilding, 365. 

Xenia, 162, 163. 

Zavitz, C. A., 230. 
Zinnia, flowers, 349. 



The Horticulturist's Rule-Book. 

A COMPENDIUM OF USEFUL INFORMATION FOR FRUIT-GROWERS 
TRUCK-GARDENERS, FLORISTS, AND OTHERS. 

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